Science.gov

Sample records for medir radios orbitales

  1. Estudio teórico del CO2. Orbitales de valencia y del ``core''

    NASA Astrophysics Data System (ADS)

    Olalla Gutiérrez, E.

    Hemos calculado las intensidades de las transiciones E1 a los miembros de las series de Rydberg con origen en los orbitales ``no enlazantes'' del dióxido de carbono, especie de conocida relevancia atmosférica. Se han computado, asimismo, los continuos de fotoionización correspondientes a los distintos canales de ionización, representándolos como densidad espectral de fuerza de oscilador frente a la energía del fotón incidente; mostramos los resultados df/dE para la fotoionización total de esta especie en el intervalo 15-60 eV. Todos los cálculos se han llevado a cabo mediante la formulación Molecular del Método de los Orbitales de Defecto Cuántico, MQDO [1,2]. La calidad de los resultados que presentamos se ha evaluado en base a la comparación con los datos, tanto experimentales como teóricos, disponibles en la bibliografía. El acuerdo encontrado es altamente satisfactorio

  2. Extensión del Formalismo de Orbitales de Defecto Cuántico al tratamiento del efecto Stark (SQDO).

    NASA Astrophysics Data System (ADS)

    Menéndez, J. M.; Martín, I.; Velasco, A. M.

    El estudio experimental de las interacciones de átomos Rydberg altamente excitados con campos eléctricos ha experimentado un creciente interés durante las dos últimas décadas debido, en gran medida, al desarrollo de nuevas técnicas para crear y estudiar átomos Rydberg en el laboratorio. Acompañando a estas nuevas técnicas experimentales, es necesario el desarrollo de modelos teóricos que nos permitan contrastar sus medidas y conocer mejor los fundamentos de los mismos. Desde el punto de vista teórico el conocimiento del desdoblamiento de los niveles energéticos de un átomo en función de la magnitud del campo eléctrico aplicado (lo que se conoce como mapa Stark) es el mejor punto de partida para la descripción del sistema y un prerrequisito fundamental para el cálculo de distintas propiedades atómicas en presencia del campo eléctrico tales como intensidades de transición, umbrales de ionización de campo eléctrico, tiempos de vida, posición y anchura de cruces evitados, etc. En este trabajo presentamos la adaptación del método de orbitales de defecto cuántico [1,2,3] al tratamiento del efecto Stark (SQDO) [4] y su aplicación al cálculo de los desdoblamientos energéticos y fuerzas de oscilador de estados Rydberg en los átomos de Li, Na y K. El propósito de este estudio es, por un lado, desarrollar métodos fiables para la determinación de propiedades atómicas en presencia de campos eléctricos y, por otro, mostrar la fiabilidad de las funciones de onda QDO en la descripción del efecto Stark en sistemas atómicos.

  3. Radio Galaxies.

    ERIC Educational Resources Information Center

    Downes, Ann

    1986-01-01

    Provides background information on radio galaxies. Topic areas addressed include: what produces the radio emission; radio telescopes; locating radio galaxies; how distances to radio galaxies are found; physics of radio galaxies; computer simulations of radio galaxies; and the evolution of radio galaxies with cosmic time. (JN)

  4. Educational Radio.

    ERIC Educational Resources Information Center

    Arafeh, Sousan

    1999-01-01

    Examines the effectiveness of the radio in education and the crucial role of the radio in distance education in first half of the 20th century; dramatic social changes in the 1960s that led to a review of educational institutions and of educational media; and the radio today as a neglected but inexpensive medium of communication that should be…

  5. Firefighters' Radios

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Public Technology Inc. asked for NASA assistance to devise the original firefighter's radio. Good short-range radio communications are essential during a fire to coordinate hose lines, rescue victims, and otherwise increase efficiency. Useful firefighting tool is lower cost, more rugged short range two-way radio. Inductorless electronic circuit replaced inductances and coils in radio circuits with combination of transistors and other low-cost components. Substitution promises reduced circuit size and cost. Enhanced electrical performance made radio more durable and improved maintainability by incorporating modular construction.

  6. Aplicación de la metodología Molecular de Orbitales de Defecto Cuántico (MQDO) al cálculo de intensidades vibrónicas y vidas medias de niveles vibracionales

    NASA Astrophysics Data System (ADS)

    María Velasco Sanz, Ana

    Desde que se formuló, en 1996, la metodología Molecular de Orbitales de Defecto Cuántico (MQDO) [1], se han obtenido datos de calidad relativos a intensidades de bandas electrónicas que implican estados Rydberg para una gran variedad de sistemas moleculares [2]. Animados por los buenos resultados obtenidos, recientemente hemos abordado el estudio de transiciones vibrónicas, es decir aquellas que ocurren entre estados vibracionales que pertenecen a distintos estados Rydberg electrónicos. Como prototipo adecuado para nuestros propósitos hemos elegido la molécula de NO, importante en la química de la atmósfera, y para la cual existen en la bibliografía datos experimentales de calidad suficiente para contrastar la validez de nuestros resultados. En concreto, hemos calculado las fuerzas de oscilador y coeficientes de Einstein para transiciones electrónicas y vibrónicas de las principales bandas del NO, al igual que vidas medias radiativas de niveles vibracionales de dicha molécula. Las propiedades estudiadas son esenciales para la comprensión de los aspectos teóricos de los procesos físicos básicos relativos a la dispersión electrónica en moléculas heteronucleares con capas abiertas. Además, valores fiables de probabilidades de transición moleculares tienen importantes aplicaciones en Astrofísica, en la modelización de procesos fotodinámicos moleculares, etc., al igual que para evaluar más profundamente la validez de nuestra metodología teórica.

  7. Radio wave.

    PubMed

    Elkin, V

    1992-01-01

    In developing countries with high rates of poverty and illiteracy, radio is emerging as an excellent medium for delivering information on health issues, family planning, nutrition, and agricultural development. Since radio does not require wired electricity, it can reach remote rural populations. Surveys have found that between 50-75% of poor rural households in developing countries own radios, and the majority listen to educational radio at least once a week. A program that reaches the urban poor outside of Lima, Peru, has been instrumental in controlling the spread of cholera. A Bolivian station broadcasts 8 hours of literacy, health, agricultural, and cultural programming a day to an audience of more than 2 million Aymara Indians. Small village radio stations with a broadcast range of 15 miles can be established for under US$400 and can generally achieve sustainability through local fundraising events such as raffles. In many cases, listeners have become broadcasters at their local radio stations. PMID:12286181

  8. Radio receivers

    NASA Astrophysics Data System (ADS)

    Bankov, V. N.; Barulin, L. G.; Zhodzishskii, M. I.; Malyshev, I. V.; Petrusinskii, V. V.

    The book is concerned with the design of microelectronic radio receivers and their components based on semiconductor and hybrid integrated circuits. Topics discussed include the hierarchical structure of radio receivers, the synthesis of structural schemes, the design of the principal functional units, and the design of radio receiver systems with digital signal processing. The discussion also covers the integrated circuits of multifunctional amplifiers, analog multipliers, charge-transfer devices, frequency filters, piezoelectronic devices, and microwave amplifiers, filters, and mixers.

  9. Educational Radio.

    ERIC Educational Resources Information Center

    Federal Communications Commission, Washington, DC.

    This report summarizes information about the history, technology, and operation of educational radio in the U.S. Also presented are the Federal Communications Commission's (FCC) rules and regulations concerning the licensing and channel assignment of educational radio, and its auxiliary special broadcast services. Included are the application…

  10. Radio astronomy

    NASA Technical Reports Server (NTRS)

    Wolken, P. R.; Schaffer, R. D.; Gorenstein, M. V.

    1981-01-01

    The activities of the Deep Space Network in support of Radio Astronomy Operations during April and May 1981 are reported. Work in progres in support of an experiment selected for use of the DSN by the Radio Astronomy Experiment Selection Panel, Twin Quasi-Stellar Object VLBI, is reported.

  11. Radio astronomy

    NASA Technical Reports Server (NTRS)

    Taylor, R. M.; Manchester, R. N.

    1980-01-01

    The activities of the Deep Space Network in support of radio and radar astronomy operations during July and August 1980 are reported. A brief update on the OSS-sponsored planetary radio astronomy experiment is provided. Also included are two updates, one each from Spain and Australia on current host country activities.

  12. Radio astronomy

    NASA Technical Reports Server (NTRS)

    Shaffer, R. D.; Wolken, P. R.; Gulkis, S.

    1981-01-01

    The activities of the Deep Space Network in support of radio astronomy operations during the first quarter of 1981 are reported. Results of the use of a low noise maser are presented, as well as updates in DSN support of experiments sanctioned by the Radio Astronomy Experiment Selection Panel.

  13. Radio Astronomy

    NASA Technical Reports Server (NTRS)

    Shaffer, R. D.; Wolken, P. R.; Niell, A. E.

    1981-01-01

    The activities of the DSN in support of Radio and Radar Astronomy Operations during September through December 1980 are described. Emphasis is on a report of an experiment selected for use of the DSN by the radio Astronomy Experiment Selection Panel: that of VLBI observations of the energetic galactic object SS-433.

  14. Radio stars.

    PubMed

    Hjellming, R M; Wade, C M

    1971-09-17

    Up to the present time six classes of radio stars have been established. The signals are almost always very faint and drastically variable. Hence their discovery has owed as much to serendipity as to the highly sophisticated equipment and techniques that have been used. When the variations are regular, as with the pulsars, this characteristic can be exploited very successfully in the search for new objects as well as in the detailed study of those that are already known. The detection of the most erratically variable radio stars, the flare stars and the x-ray stars, is primarily a matter of luck and patience. In the case of the novas, one at least knows where and oughly when to look for radio emission. A very sensitive interferometer is clearly the best instrument to use in the initial detection of a radio star. The fact that weak background sources are frequently present makes it essential to prove that the position of a radio source agrees with that of a star to within a few arc seconds. The potential of radio astronomy for the study of radio stars will not be realized until more powerful instruments than those that are available today can be utilized. So far, we have been able to see only the most luminous of the radio stars. PMID:17836594

  15. College Radio.

    ERIC Educational Resources Information Center

    Sauls, Samuel J.

    As with commercial stations, the underlying premise of the college radio station is to serve the community, whether it be the campus community or the community at large, but in unique ways often geared to underserved niches of the population. Much of college radio's charm lies in its unpredictable nature and constant mutations. The stations give…

  16. Radio Pulsars

    NASA Astrophysics Data System (ADS)

    Beskin, V. S.; Chernov, S. V.; Gwinn, C. R.; Tchekhovskoy, A. A.

    2015-10-01

    Almost 50 years after radio pulsars were discovered in 1967, our understanding of these objects remains incomplete. On the one hand, within a few years it became clear that neutron star rotation gives rise to the extremely stable sequence of radio pulses, that the kinetic energy of rotation provides the reservoir of energy, and that electromagnetic fields are the braking mechanism. On the other hand, no consensus regarding the mechanism of coherent radio emission or the conversion of electromagnetic energy to particle energy yet exists. In this review, we report on three aspects of pulsar structure that have seen recent progress: the self-consistent theory of the magnetosphere of an oblique magnetic rotator; the location, geometry, and optics of radio emission; and evolution of the angle between spin and magnetic axes. These allow us to take the next step in understanding the physical nature of the pulsar activity.

  17. Radio Astronomy

    NASA Technical Reports Server (NTRS)

    Wolken, P. R.; Shaffer, R. D.

    1983-01-01

    Deep Space Network (DSN) 26- and 64-meter antenna stations were utilized in support of Radio Astronomy Experiment Selection Panel experiments. Within a time span of 10 days, in May 1983 (267.75 hours total), nine RAES experiments were supported. Most of these experiments involved multifacility interferometry using Mark 3 data recording terminals and as many as six non-DSN observatories. Investigations of black holes, quasars, galaxies, and radio sources are discussed.

  18. Radio astronomy

    NASA Technical Reports Server (NTRS)

    Kellermann, Kenneth I.; Heeschen, David; Backer, Donald C.; Cohen, Marshall H.; Davis, Michael; Depater, Imke; Deyoung, David; Dulk, George A.; Fisher, J. R.; Goss, W. Miller

    1991-01-01

    The following subject areas are covered: (1) scientific opportunities (millimeter and sub-millimeter wavelength astronomy; meter to hectometer astronomy; the Sun, stars, pulsars, interstellar masers, and extrasolar planets; the planets, asteroids, and comets; radio galaxies, quasars, and cosmology; and challenges for radio astronomy in the 1990's); (2) recommendations for new facilities (the millimeter arrays, medium scale instruments, and small-scale projects); (3) continuing activities and maintenance, upgrading of telescopes and instrumentation; (4) long range programs and technology development; and (5) social, political, and organizational considerations.

  19. The Radio JOVE Project - Shoestring Radio Astronomy

    NASA Technical Reports Server (NTRS)

    Thieman, J.; Flagg, R.; Greenman, W.; Higgins, C.; Reyes, F.; Sky, J.

    2010-01-01

    Radio JOVE is an education and outreach project intended to give students and other interested individuals hands-on experience in learning radio astronomy. They can do this through building a radio telescope from a relatively inexpensive kit that includes the parts for a receiver and an antenna as well as software for a computer chart recorder emulator (Radio Skypipe) and other reference materials

  20. Space Telecommunications Radio System STRS Cognitive Radio

    NASA Technical Reports Server (NTRS)

    Briones, Janette C.; Handler, Louis M.

    2013-01-01

    Radios today are evolving from awareness toward cognition. A software defined radio (SDR) provides the most capability for integrating autonomic decision making ability and allows the incremental evolution toward a cognitive radio. This cognitive radio technology will impact NASA space communications in areas such as spectrum utilization, interoperability, network operations, and radio resource management over a wide range of operating conditions. NASAs cognitive radio will build upon the infrastructure being developed by Space Telecommunication Radio System (STRS) SDR technology. This paper explores the feasibility of inserting cognitive capabilities in the NASA STRS architecture and the interfaces between the cognitive engine and the STRS radio. The STRS architecture defines methods that can inform the cognitive engine about the radio environment so that the cognitive engine can learn autonomously from experience, and take appropriate actions to adapt the radio operating characteristics and optimize performance.

  1. RADIO ALTIMETERS

    DOEpatents

    Bogle, R.W.

    1960-11-22

    A radio ranging device is described which utilizes a superregenerative oscillator having alternate sending and receiving phases with an intervening ranging interval between said phases, means for varying said ranging interval, means responsive to an on-range noise reduction condition for stopping said means for varying the ranging interval and indicating means coupled to the ranging interval varying means and calibrated in accordance with one-half the product of the ranging interval times the velocity of light whereby the range is indicated.

  2. Radio Jove: Jupiter Radio Astronomy for Citizens

    NASA Astrophysics Data System (ADS)

    Higgins, Charles; Thieman, J. R.; Flagg, R.; Reyes, F. J.; Sky, J.; Greenman, W.; Brown, J.; Typinski, D.; Ashcraft, T.; Mount, A.

    2014-01-01

    Radio JOVE is a hands-on educational activity that brings the radio sounds of the Sun, Jupiter, the Milky Way Galaxy, and terrestrial radio noise to students, teachers, and the general public. Participants may build a simple radio telescope kit, make scientific observations, and interact with professional radio observatories in real-time over the Internet. Our website (http://radiojove.gsfc.nasa.gov) includes science information, construction manuals, observing guides, and education resources for teachers and students. Radio Jove is continually expanding its participants with over 1800 kits sold to more than 70 countries worldwide. Recently some of our most dedicated observers have upgraded their Radio Jove antennas to semi-professional observatories. We have spectrographs and wide band antennas, some with 8 MHz bandwidth and some with dual polarization capabilities. In an effort to add to the science literature, these observers are coordinating their efforts to pursue some basic questions about Jupiter’s radio emissions (radio source locations, spectral structure, long term changes, etc.). We can compare signal and ionosphere variations using the many Radio Jove observers at different locations. Observers are also working with members of the Long Wavelength Array Station 1 (LWA1) radio telescope to coordinate observations of Jupiter; Radio Jove is planning to make coordinated observations while the Juno Mission is active beginning in 2015. The Radio Jove program is overviewed, its hardware and software are highlighted, recent sample observations are shown, and we demonstrate that we are capable of real citizen science.

  3. Radio tracking system

    NASA Technical Reports Server (NTRS)

    Breidenthal, J. C.; Komarek, T. A.

    1982-01-01

    The principles and techniques of deep space radio tracking are described along with the uses of tracking data in navigation and radio science. Emphasis is placed on the measurement functions of radio tracking.

  4. Soviet radio telescopes and solar radio astronomy

    NASA Astrophysics Data System (ADS)

    Alekseev, V. A.; Gel'Freikh, Georgii B.; Zaitsev, Valerii V.; Iliasov, Iurii P.; Kaidanovskii, N. L.

    Soviet radio telescopes of different type and purpose are described, with particular emphasis on very long baseline interferometry. Soviet radio-astronomy studies of solar radio emission and the interplanetary medium are also discussed, with particular attention given to the investigation of the sun's supercorona and the interplanetary plasma.

  5. The Radio Amateur's Handbook.

    ERIC Educational Resources Information Center

    Blakeslee, Douglas, Ed.

    The objectives of this basic reference work for the radio amateur are to present radio theory and practice in terms of application and to reflect both the fundamentals and the rapidly-advancing technology of radio communications so that the radio amateur will have a guide to what is practical, meaningful, proven, and useful. Twenty-three chapters…

  6. The Frequency Spectrum Radio.

    ERIC Educational Resources Information Center

    Howkins, John, Ed.

    1979-01-01

    This journal issue focuses on the frequency spectrum used in radio communication and on the World Administrative Radio Conference, sponsored by the International Telecommunication Union, held in Geneva, Switzerland, in the fall of 1979. Articles describe the World Administrative Radio Conference as the most important radio communication conference…

  7. Radio frequency detection assembly and method for detecting radio frequencies

    SciTech Connect

    Cown, Steven H.; Derr, Kurt Warren

    2010-03-16

    A radio frequency detection assembly is described and which includes a radio frequency detector which detects a radio frequency emission produced by a radio frequency emitter from a given location which is remote relative to the radio frequency detector; a location assembly electrically coupled with the radio frequency detector and which is operable to estimate the location of the radio frequency emitter from the radio frequency emission which has been received; and a radio frequency transmitter electrically coupled with the radio frequency detector and the location assembly, and which transmits a radio frequency signal which reports the presence of the radio frequency emitter.

  8. Resonance and Radio

    ERIC Educational Resources Information Center

    Starrett, Malin J.

    2008-01-01

    The science and technology of radio receives little attention in contemporary education. This article discusses ways to explore the basic operating principles of radio. (Contains 4 figures, 3 footnotes, and 2 notes.)

  9. Triggered Jovian radio emissions

    NASA Technical Reports Server (NTRS)

    Calvert, W.

    1985-01-01

    Certain Jovian radio emissions seem to be triggered from outside, by much weaker radio waves from the sun. Recently found in the Voyager observations near Jupiter, such triggering occurs at hectometric wavelengths during the arrival of solar radio bursts, with the triggered emissions lasting sometimes more than an hour as they slowly drifted toward higher frequencies. Like the previous discovery of similar triggered emissions at the earth, this suggests that Jupiter's emissions might also originate from natural radio lasers.

  10. Commercial Radio as Communication.

    ERIC Educational Resources Information Center

    Rothenbuhler, Eric W.

    1996-01-01

    Compares the day-to-day work routines of commercial radio with the principles of a theoretical communication model. Illuminates peculiarities of the conduct of communication by commercial radio. Discusses the application of theoretical models to the evaluation of practicing institutions. Offers assessments of commercial radio deriving from…

  11. Extragalactic Radio Sources

    ERIC Educational Resources Information Center

    Kellerman, Kenneth I.

    1973-01-01

    Discusses new problems arising from the growing observational data through radio telescope arrays, involving the origin of radio sources, apparent superluminal velocities, conversion of radio sources to relativistic particles, and the nature of compact opaque and extended transparent sources. New physics may be needed to answer these cosmological…

  12. Stellar radio emission (Review)

    NASA Astrophysics Data System (ADS)

    Zhelezniakov, V. V.

    The current understanding of the radio-emission characteristics of 'ordinary' main sequence stars as well as giants and supergiants is examined. Particular consideration is given to radio emission from supergiants, Young T Tauri stars, magnetic Ap stars, flare stars of UV Ceti type, Alpha Sco, and RS CVn objects. It is noted that the study of stellar radio emission is in its initial stage. Further progress in this area depends on successes in finding new radio sources, associated, for example, with magnetic stars, and on an intensified investigation of the frequency spectra and polarization of already-discovered radio stars. It is also noted that, although the current knowledge of solar physics can help in understanding stellar radio emission, models and ideas developed for solar conditions should not be mechanically transferred to other stars by a simple change in scale.

  13. STEM on the radio

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2011-10-01

    Looking for an Internet radio station focusing on programing about science, technology, engineering, and math (STEM)? The U.S. National Science Foundation (NSF) announced on 26 September the launch of Science360 Radio, which it says is the first Internet radio stream dedicated to STEM programing. Science360 includes more than 100 radio shows and podcasts that are available on the Web as well as on iPhone and Android devices. The shows originate from a variety of sources, including NSF, other U.S. government agencies, science organizations, universities, and media outlets. For more information, see http://science360.gov/files/.

  14. Radio data transmission for SCADA

    SciTech Connect

    Frasier, W.E. )

    1989-09-01

    Enron has used such wireless systems as meteor burst radio, 952 MHz multiple address radio, VSAT and L-band satellite, cellular radio and ACSB radio. The company's experience with meteor burst radio communications is discussed in this paper. It indicates good system reliability and consequently all back-up telephone lines have been removed from sites using this system.

  15. Desarrollo de un instrumento para medir percepciones sobre el contexto de construccion del conocimiento cientifico de estudiantes universitarios de nuevo ingreso

    NASA Astrophysics Data System (ADS)

    Garcia-Ramirez, Jaime Antonio

    En esta investigacion, se desarrollo un instrumento que permite medir percepciones relacionadas al contexto de constriccion del conocimiento cientifico. Se examinaron instrumentos existentes y se encontro que el VOSTS (Views on science, technology, and society), instrumento desarrollado empiricamente en Canada por Aikenhead, Ryan y Fleming, podia traducirse y validarse en el contexto cultural puertorriqueno. El instrumento es extenso, consta de 113 reactivos, cada uno con una premisa basica relacionada a la tematica ciencia, tecnologia y sociedad y un numero de alternativas relacionadas a la premisa que oscila entre siete y trece. Se delimito su utilizacion a los quince reactivos identificados por los autores como relacionados a la construccion social del conocimiento cientifico. Metodologicamente, se procedio a utilizar el modelo de adaptacion intercultural, que permite que el instrumento desarrollado satisfaga las dimensiones de equivalencia semantica, de contenido, tecnica, de criterio y conceptual, atemperado asi al instrumento original. Se cumplio con este proposito mediante la traduccion de la version original en ingles al espanol y viceversa. Se utilizaron comites para examinar la traduccion y la retro-traduccion del instrumento. Se realizo una prueba piloto con estudiantes universitarios de nuevo ingreso, utilizando el instrumento traducido para asegurar su intelegibilidad. La confiabilidad del instrumento se determino mediante la intervencion de un panel de expertos quienes clasificaron las distintas posiciones dentro de cada reactivo en: realista, con merito e ingenua; se transformaron estas opciones en valores numericos lo que permitio establecer una escala Likert para cada una. Se suministro el instrumento a una muestra de estudiantes universitarios de nuevo ingreso con caracteristicas similares a las de la poblacion puertorriquena en cuanto a ejecucion en las pruebas de aptitud verbal y matematica del College Board. Los resultados de sus contestaciones

  16. Radio Frequency Interference and the National Radio Astronomy Observatory

    NASA Astrophysics Data System (ADS)

    Smith, Sierra

    2014-01-01

    Radio frequency interference (RFI) and radio astronomy have been closely linked since the emergence of radio astronomy as a scientific discipline in the 1930s. Even before the official establishment of the National Radio Astronomy Observatory, protection against contemporary and future radio noise levels was seen as crucial to ensure success of any new observatory. My talk will examine the various local, regional, national, and international efforts enacted to protect NRAO and other American radio astronomy sites from RFI.

  17. Broadcast Management: Radio; Television.

    ERIC Educational Resources Information Center

    Quaal, Ward L.; Martin, Leo A.

    After outlining the qualities necessary in a good radio or television manager, the book describes his duties which fall in three major areas: programming, engineering, and sales. It discusses the relationship between the station and its audience in detail. Sections on radio and television programming describe the way most stations operate and…

  18. Film, Radio, and Television.

    ERIC Educational Resources Information Center

    Hardesty, Carolyn, Ed.

    1990-01-01

    This journal issue covers the history of film, radio, and television in Iowa. The first article, "When Pictures and Sound Came to Iowa," summarizes the origin of movies and radio and their early beginnings in Iowa. Using old photographs and measurement charts, the viewing, reading, and listening habits of young people in 1950 and 1958 are…

  19. Amateur Radio Satellite Communications.

    ERIC Educational Resources Information Center

    Koch, David P.

    The Amateur Radio Satellite Communications project had, as its goal, the assembly of an amateur radio satellite station in a high school physics classroom. Specific objectives were to provide: (1) a special source of interest as a motivator for attracting students and building public relations; (2) a center of interest as a motivator for the study…

  20. Stabilized radio frequency quadrupole

    DOEpatents

    Lancaster, Henry D.; Fugitt, Jock A.; Howard, Donald R.

    1984-01-01

    A long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator.

  1. Stabilized radio frequency quadrupole

    DOEpatents

    Lancaster, H.D.; Fugitt, J.A.; Howard, D.R.

    1984-12-25

    Disclosed is a long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator. 5 figs.

  2. The Radio Jove Project

    NASA Technical Reports Server (NTRS)

    Thieman, J. R.

    2010-01-01

    The Radio love Project is a hands-on education and outreach project in which students, or any other interested individuals or groups build a radio telescope from a kit, operate the radio telescope, transmit the resulting signals through the internet if desired, analyze the results, and share the results with others through archives or general discussions among the observers. Radio love is intended to provide an introduction to radio astronomy for the observer. The equipment allows the user to observe radio signals from Jupiter, the Sun, the galaxy, and Earth-based radiation both natural and man-made. The project was started through a NASA Director's Discretionary Fund grant more than ten years ago. it has continued to be carried out through the dedicated efforts of a group of mainly volunteers. Dearly 1500 kits have been distributed throughout the world. Participation can also be done without building a kit. Pre-built kits are available. Users can also monitor remote radio telescopes through the internet using free downloadable software available through the radiosky.com website. There have been many stories of prize-winning projects, inspirational results, collaborative efforts, etc. We continue to build the community of observers and are always open to new thoughts about how to inspire the observers to still greater involvement in the science and technology associated with Radio Jove.

  3. Optical and radio rangefinders

    NASA Astrophysics Data System (ADS)

    Kostetskaia, Iaromira Mikhailovna

    This handbook expounds the theory of optical and radio rangefinders and radiogeodesic systems. Particular attention is given to instrument design, investigations using geodesic phase rangefinders, ranging errors, and the effect of meteorological factors in the atmospheric surface layer. Applications of optical and radio rangefinders are considered, including the establishment of geodetic networks and the assessment of the accuracy of triangulation networks.

  4. Planetary radio lasing

    NASA Technical Reports Server (NTRS)

    Calvert, W.

    1988-01-01

    Both the Earth's auroral kilometric radiation (AKR) and Jupiter's decametric radio S-bursts are attributed to natural radio lasing. Presumably consisting of self-excited, closed-loop wave feedback oscillations between local irregularities of the source plasma density, this radio lasing is comparable to that which occurs in man-made optical lasers, although at radio, rather than optical wavelengths. As a result, it should produce a multiple discrete emission spectrum and intense, coherent beams. Recent observations of the AKR's discreteness and coherence have clearly ruled out the previous open-loop amplifier model for such emissions, and recent observations of the Jovian S-bursts have shown the expected, regularly-spaced, longitudinal laser modes. These new observations thus confirm the proposed planetary cyclotron radio lasing at both planets.

  5. Radio efficiency of pulsars

    SciTech Connect

    Szary, Andrzej; Melikidze, George I.; Gil, Janusz; Zhang, Bing; Xu, Ren-Xin E-mail: zhang@physics.unlv.edu

    2014-03-20

    We investigate radio emission efficiency, ξ, of pulsars and report a near-linear inverse correlation between ξ and the spin-down power, E-dot , as well as a near-linear correlation between ξ and pulsar age, τ. This is a consequence of very weak, if any, dependences of radio luminosity, L, on pulsar period, P, and the period derivative, P-dot , in contrast to X-ray or γ-ray emission luminosities. The analysis of radio fluxes suggests that these correlations are not due to a selection effect, but are intrinsic to the pulsar radio emission physics. We have found that, although with a large variance, the radio luminosity of pulsars is ≈10{sup 29} erg s{sup –1}, regardless of the position in the P-- P-dot diagram. Within such a picture, a model-independent statement can be made that the death line of radio pulsars corresponds to an upper limit in the efficiency of radio emission. If we introduce the maximum value for radio efficiency into the Monte Carlo-based population syntheses we can reproduce the observed sample using the random luminosity model. Using the Kolmogorov-Smirnov test on a synthetic flux distribution reveals a high probability of reproducing the observed distribution. Our results suggest that the plasma responsible for generating radio emission is produced under similar conditions regardless of pulsar age, dipolar magnetic field strength, and spin-down rate. The magnetic fields near the pulsar surface are likely dominated by crust-anchored, magnetic anomalies, which do not significantly differ among pulsars, leading to similar conditions for generating electron-positron pairs necessary to power radio emission.

  6. Radio broadcasting via satellite

    NASA Astrophysics Data System (ADS)

    Helm, Neil R.; Pritchard, Wilbur L.

    1990-10-01

    Market areas offering potential for future narrowband broadcast satellites are examined, including international public diplomacy, government- and advertising-supported, and business-application usages. Technical issues such as frequency allocation, spacecraft types, transmission parameters, and radio receiver characteristics are outlined. Service and system requirements, advertising revenue, and business communications services are among the economic issues discussed. The institutional framework required to provide an operational radio broadcast service is studied, and new initiatives in direct broadcast audio radio systems, encompassing studies, tests, in-orbit demonstrations of, and proposals for national and international commercial broadcast services are considered.

  7. Packet Radio for Library Automation.

    ERIC Educational Resources Information Center

    Brownrigg, Edwin B.; And Others

    1984-01-01

    This tutorial on packet radio (communication system using radio and digital packet-switching technology) highlights radio transmission of data, brief history, special considerations in applying packet radio to library online catalogs, technology, defining protocol at physical and network levels, security, geographic coverage, and components. (A…

  8. Eratosthenes via Ham Radio

    ERIC Educational Resources Information Center

    Koser, John F.

    1975-01-01

    A secondary geology class used Eratosthenes' method for measuring the circumference of the earth by comparing their measurements of the shadow of a vertical rod to the measurements made by another person contacted by ham radio. (MLH)

  9. Division x: Radio Astronomy

    NASA Astrophysics Data System (ADS)

    Taylor, Russ; Chapman, Jessica; Rendong, Nan; Carilli, Christopher; Giovannini, Gabriele; Hills, Richard; Hirabayashi, Hisashi; Jonas, Justin; Lazio, Joseph; Morganti, Raffaella; Rubio, Monica; Shastri, Prajval

    2012-04-01

    This triennium has seen a phenomenal investment in development of observational radio astronomy facilities in all parts of the globe at a scale that significantly impacts the international community. This includes both major enhancements such as the transition from the VLA to the EVLA in North America, and the development of new facilities such as LOFAR, ALMA, FAST, and Square Kilometre Array precursor telescopes in Australia and South Africa. These developments are driven by advances in radio-frequency, digital and information technologies that tremendously enhance the capabilities in radio astronomy. These new developments foreshadow major scientific advances driven by radio observations in the next triennium. We highlight these facility developments in section 3 of this report. A selection of science highlight from this triennium are summarized in section 2.

  10. The Radio JOVE Project

    NASA Astrophysics Data System (ADS)

    Garcia, L.; Thieman, J.; Higgins, C.

    1999-09-01

    Radio JOVE is an interactive educational activity which brings the radio sounds of Jupiter and the Sun to students, teachers, and the general public. This is accomplished through the construction of a simple radio telescope kit and the use of a real-time radio observatory on the Internet. Our website (http://radiojove.gsfc.nasa.gov/) will contain science information, instruction manuals, observing guides, and education resources for students and teachers. Our target audience is high school science classes, but subjects can be tailored to college undergraduate physics and astronomy courses or even to middle school science classes. The goals of the project are: 1) Educate people about planetary and solar radio astronomy, space physics, and the scientific method 2) Provide teachers and students with a hands-on radio astronomy exercise as a science curriculum support activity by building and using a simple radio telescope receiver/antenna kit 3) Create the first ever online radio observatory which provides real-time data for those with internet access 4) Allow interactions among participating schools by facilitating exchanges of ideas, data, and observing experiences. Our current funding will allow us to impact 100 schools by partially subsidizing their participation in the program. We expect to expand well beyond this number as publicity and general interest increase. Additional schools are welcome to fully participate, but we will not be able to subsidize their kit purchases. We hope to make a wide impact among the schools by advertising through appropriate newsletters, space grant consortia, the INSPIRE project (http://image.gsfc.nasa.gov/poetry/inspire/), electronic links, and science and education meetings. We would like to acknoledge support from the NASA/GSFC Director's Discretionary Fund, the STScI IDEAS grant program and the NASA/GSFC Space Science Data Operations Office.

  11. Conceptual Background to Radio

    NASA Astrophysics Data System (ADS)

    Ponsonby, J. E. B.

    2004-06-01

    The International Telecommunications Union (ITU) conceives the radio spectrum as primarily a resource for telecommunications. Indeed most applications of radio are for communications and other radio services, particularly the Radio Astronomy Service, are deemed to be `pretend'communication serviceas for spectrum amnagement purposes. The language of Radio Spectrum Management is permeated by the terminology ofcommunications, some derived from the physics of radio and some from aspects of information theory. This contribution touches on all the essential concepts of radiocommunications which the author thinks should be the common mental equipment of the Spectrum Manager. The fundamental capacity of a communication channel is discussed in terms of the degrees of freedom and bandwidth of a signal, and the signal to noise ratio. It is emphasized that an information bearing signal is inherently unpredictable, and must, at some level, be discontinuous. This has important consequences for the form of its power spectrum. The effect of inserting filters is discussed particularly with regard to constant amplitude signals and, in the context of non-linear power amplifiers, the phenomenon of`sideband recovery'. All the common generic forms of modulation are discussed including the very different case of `no-modulation' which applies in all forms of passive remote sensing. Whilst all are agreed that the radio spectrum should be used `efficiently', there is no quantitative measure of spectral efficiency which embraces all relevant aspects of spectral usage. These various aspects are dicussed. Finally a brief outline of some aspects of antennae are reviewed. It is pointed out that the recent introduction of so-called `active antennnae', which have properties unlike traditional passive antennae, has confused the interpretation of those ITU Radio Regulations which refer to antennae.

  12. Astrometry of southern radio sources

    NASA Technical Reports Server (NTRS)

    White, Graeme L.; Jauncey, David L.; Harvey, Bruce R.; Savage, Ann; Gulkis, Samuel; Preston, Robert A.

    1991-01-01

    An overview is presented of a number of astrometry and astrophysics programs based on radio sources from the Parkes 2.7 GHz catalogs. The programs cover the optical identification and spectroscopy of flat-spectrum Parkes sources and the determination of their milliarcsecond radio structures and positions. Work is also in progress to tie together the radio and Hipparcos positional reference frames. A parallel program of radio and optical astrometry of southern radio stars is also under way.

  13. Radio emission from supernovae.

    NASA Astrophysics Data System (ADS)

    Weiler, K. W.; Panagia, N.; Sramek, R. A.; Van Dyk, S. D.; Stockdale, C. J.; Williams, C. L.

    Study of radio supernovae over the past 30 years includes more than three dozen detected objects and more than 150 upper limits. From this work it is possible to identify classes of radio properties, demonstrate conformance to and deviations from existing models, estimate the density and structure of the circumstellar material and, by inference, the evolution of the presupernova stellar wind, and reveal the last stages of stellar evolution before explosion. Along with reviewing these general properties of the radio emission from supernovae, we present our extensive observations of the radio emission from supernova (SN) 1993J in M 81 (NGC 3031) made with the Very Large Array and other radio telescopes. The SN 1993J radio emission evolves regularly in both time and frequency, and the usual interpretation in terms of shock interaction with a circumstellar medium (CSM) formed by a pre-supernova stellar wind describes the observations rather well considering the complexity of the phenomenon. However: 1) The highest frequency measurements at 85 - 110 GHz at early times (<40 days) are not well fitted by the parameterization which describes the cm wavelength measurements. 2) At a time ˜3100 days after shock breakout, the decline rate of the radio emission steepens from (t+beta ) beta ˜ -0.7 to beta ˜ -2.7 without change in the spectral index (nu +alpha ; alpha ˜ -0.81). This decline is best described not as a power-law, but as an exponential decay with an e-folding time of ˜ 1100 days. 3) The best overall fit to all of the data is a model including both non-thermal synchrotron self-absorption (SSA) and a thermal free-free absorbing (FFA) components at early times, evolving to a constant spectral index, optically thin decline rate, until a break in that decline rate at day ˜3100, as mentioned above.

  14. Educational Radio. Information Bulletin 21-B.

    ERIC Educational Resources Information Center

    Federal Communications Commission, Washington, DC.

    The term "Educational Radio" includes all radio stations licensed for noncommercial operation. A history of educational radio begins with the first domestic law for control of radio in general, The Radio Act of 1912. Federal Communication Commission (FCC) regulations pertaining to educational radio or "public radio" deal with channel assignments,…

  15. Double Radio Sources: Two Approaches

    NASA Astrophysics Data System (ADS)

    Valtonen, M. J.; Heinämäki, P.

    2000-02-01

    The theory of double radio sources is considered from two different points of view: the so called unified models and the slingshot model. First, observations and theory are discussed in 11 areas: (1) the dependence or independence of small-scale and large-scale jets from each other; (2) stability and existence of large-scale jets; (3) radio hot spots inside the lobes of double radio sources; (4) the relation of double-lobed quasars to radio galaxies; (5) polarization and other asymmetries between the two lobes and correlations among them; (6) the speeds of advance of radio lobes; (7) giant radio sources; (8) one-sided double radio sources; (9) multiple-sided double radio sources; (10) the origin of the Fanaroff-Riley classes of radio morphology; and (11) the origin of distance asymmetries of the radio lobes. Then five steps in building up a double radio source theory are discussed: (1) theory of galaxy mergers; (2) theory of black hole mergers; (3) theory of black hole interactions and ejections; (4) theory of radio lobe formation and evolution; and (5) radio jet theory. Finally, recent X-ray observations by ROSAT are discussed from the point of view of double radio source theory.

  16. The Smiley Radio Telescope

    NASA Astrophysics Data System (ADS)

    Blake, R. M.; Castelaz, M. W.; Daugherty, J.; Owen, L.

    2004-12-01

    More than ever modern astronomy is based upon a multi-wavelength approach combining data-sets from optical, infrared, radio, X-ray and gamma ray observatories to provide improved understanding of astrophysical phenomena. In the field of astronomy education however, until recently most teaching resources available to high schools have been limited to small optical telescopes, with little coverage of other branches of observational astronomy. To fill in this resource gap, PARI has developed the School of Galactic Radio Astronomy and the Smiley 4.6 m Radio Telescope to provide high schools access to a state-of-the-art, internet accessable radio observatory for class projects and activities. We describe here the development of the Smiley radio telescope, its control systems and give examples of several class activities which have been developed for use by high school students. We describe the future development of Smiley and plans to upgrade its performance. The SGRA has been supported by grants from Progress Energy, Z. Smith Reynolds, STScI IDEAS, and the AAS Small Research Grant Program which is supported by NASA.

  17. Giant radio pulses

    NASA Astrophysics Data System (ADS)

    Kondratiev, Vladislav

    Rotation-powered radio pulsars exhibit a remarkably diverse spectrum of variability with characteristic time scales from days and even years (intermittent pulsars) to minutes-seconds (nulling) and (sub-)microseconds. The latter time scales are associated with the phenomenon of giant pulses (GPs) and micropulses. The story of GPs started in 1968, when Staelin and Reifenstein discovered the Crab pulsar through its spectacularly bright radio pulses. To date, only seven pulsars out of more than 2200 are known to show GP emission, namely the pulsars B0531+21, B1937+21, B0540-69, B1821-24, B1957+20, J0218+4232, and B1820-30A. Giant pulses are characterized by large energies (more than ten times of the energy of the average pulse), short durations, power-law energy distribution, specific rotational phase of occurrence, high degree of polarization, and accompanying high-energy radiation. Large energies of GPs and coincidence of their phase of occurrence with peaks of high-energy profiles hint at the same mechanism of radio GP and high-energy emission. The correlation of Crab pulsar GPs with optical, X-ray and gamma-ray photons was studied for the past 20 years, with only radio/optical link confirmed so far. In my talk I will present the summary of the observational evidence of radio GPs and give an overview of theoretical advances on giant-pulse emission mechanism.

  18. Galileo radio science investigations

    NASA Technical Reports Server (NTRS)

    Howard, H. T.; Eshleman, V. R.; Hinson, D. P.; Kliore, A. J.; Lindal, G. F.; Woo, R.; Bird, M. K.; Volland, H.; Edenhoffer, P.; Paetzold, M.

    1992-01-01

    Galileo radio-propagation experiments are based on measurements of absolute and differential propagation time delay, differential phase delay, Doppler shift, signal strength, and polarization. These measurements can be used to study: the atmospheric and ionospheric structure, constituents, and dynamics of Jupiter; the magnetic field of Jupiter; the diameter of Io, its ionospheric structure, and the distribution of plasma in the Io torus; the diameters of the other Galilean satellites, certain properties of their surfaces, and possibly their atmospheres and ionospheres; and the plasma dynamics and magnetic field of the solar corona. The spacecraft system provides linear rather than circular polarization on the S-band downlink signal, the capability to receive X-band uplink signals, and a differential downlink ranging mode. A highly-stable, dual-frequency, spacecraft radio system is developed that is suitable for simultaneous measurements of all the parameters normally attributed to radio waves.

  19. Planetary radio waves

    NASA Technical Reports Server (NTRS)

    Goertz, C. K.

    1986-01-01

    Three planets, the earth, Jupiter and Saturn are known to emit nonthermal radio waves which require coherent radiation processes. The characteristic features (frequency spectrum, polarization, occurrence probability, radiation pattern) are discussed. Radiation which is externally controlled by the solar wind is distinguished from internally controlled radiation which only originates from Jupiter. The efficiency of the externally controlled radiation is roughly the same at all three planets (5 x 10 to the -6th) suggesting that similar processes are active there. The maser radiation mechanism for the generation of the radio waves and general requirements for the mechanism which couples the power generator to the region where the radio waves are generated are briefly discussed.

  20. Radio Emission from Supernovae

    NASA Astrophysics Data System (ADS)

    Weiler, Kurt W.; Panagia, Nino; Sramek, Richard A.; van Dyk, Schuyler D.; Williams, Christopher L.; Stockdale, Christopher J.; Kelley, Matthew T.

    2007-10-01

    Study of radio supernovae over the past 27 years includes more than three dozen detected objects and more than 150 upper limits. From this work it is possible to identify classes of radio properties, demonstrate conformance to and deviations from existing models, estimate the density and structure of the circumstellar material and, by inference, the evolution of the presupernova stellar wind, and reveal the last stages of stellar evolution before explosion. It is also possible to detect ionized hydrogen along the line of sight, to demonstrate binary properties of the presupernova stellar system, and to detect clumpiness of the circumstellar material. Along with reviewing these general properties of the radio emission from supernovae, we present our extensive observations of the radio emission from supernova (SN) 1993J in M 81 (NGC 3031) made with the Very Large Array and other radio telescopes. The SN 1993J radio emission evolves regularly in both time and frequency, and the usual interpretation in terms of shock interaction with a circumstellar medium (CSM) formed by a pre-supernova stellar wind describes the observations rather well considering the complexity of the phenomenon. However: 1) The highest frequency measurements at 85-110 GHz at early times (<40 days) are not well fitted by the parameterization which describes the cm wavelength measurements rather well. 2) At mid-cm wavelengths there is often deviation from the fitted radio light curves, particularly near the peak flux density, and considerable shorter term deviations in the declining portion when the emission has become optically thin. 3) At a time ~3100 days after shock breakout, the decline rate of the radio emission steepens from (t+β)β~-0.7 to β~-2.7 without change in the spectral index (ν+αα~-0.81). However, this decline is best described not as a power-law, but as an exponential decay starting at day ~3100 with an e-folding time of ~1100 days. 4) The best overall fit to all of the data is

  1. Sensors Locate Radio Interference

    NASA Technical Reports Server (NTRS)

    2009-01-01

    After receiving a NASA Small Business Innovation Research (SBIR) contract from Kennedy Space Center, Soneticom Inc., based in West Melbourne, Florida, created algorithms for time difference of arrival and radio interferometry, which it used in its Lynx Location System (LLS) to locate electromagnetic interference that can disrupt radio communications. Soneticom is collaborating with the Federal Aviation Administration (FAA) to install and test the LLS at its field test center in New Jersey in preparation for deploying the LLS at commercial airports. The software collects data from each sensor in order to compute the location of the interfering emitter.

  2. Radio astronomy with microspacecraft

    NASA Technical Reports Server (NTRS)

    Collins, D.

    2001-01-01

    A dynamic constellation of microspacecraft in lunar orbit can carry out valuable radio astronomy investigations in the frequency range of 30kHz--30MHz, a range that is difficult to explore from Earth. In contrast to the radio astronomy ivestigations that have flown on individual spacecraft, the four microspacecraft together with a carrier spacecraft, which transported them to lunar orbit, form an interferometer with far superior angular resolution. Use of microspacecraft allows the entire constellation to be launched with a Taurus-class vehicle. Also distinguishing this approach is that the Moon is used as needed to shield the constellation from RF interference from the Earth and Sun.

  3. Radio Emission from Supernovae

    SciTech Connect

    Weiler, Kurt W.; Panagia, Nino; Sramek, Richard A.; Van Dyk, Schuyler D.; Stockdale, Christopher J.; Kelley, Matthew T.

    2009-05-03

    Study of radio supernovae over the past 27 years includes more than three dozen detected objects and more than 150 upper limits. From this work it is possible to identify classes of radio properties, demonstrate conformance to and deviations from existing models, estimate the density and structure of the circumstellar material and, by inference, the evolution of the presupernova stellar wind, and reveal the last stages of stellar evolution before explosion. It is also possible to detect ionized hydrogen along the line of sight, to demonstrate binary properties of the presupernova stellar system, and to detect dumpiness of the circumstellar material.

  4. e-POP Radio Science Using Amateur Radio Transmissions

    NASA Astrophysics Data System (ADS)

    Frissell, N. A.; Perry, G. W.; Miller, E. S.; Shovkoplyas, A.; Moses, M. L.; James, H. G.; Yau, A. W.

    2015-12-01

    A major component of the enhanced Polar Outflow Probe (e-POP) Radio Receiver Instrument (RRI) mission is to utilize artificially generated radio emissions to study High Frequency (HF) radio wave propagation in the ionosphere. In the North American and European sectors, communications between amateur radio operators are a persistent and abundant source source of HF transmissions. We present the results of HF radio wave propagation experiments using amateur radio transmissions as an HF source for e-POP RRI. We detail how a distributed and autonomously operated amateur radio network can be leveraged to study HF radio wave propagation as well as the structuring and dynamics of the ionosphere over a large geographic region. In one case, the sudden disappearance of nearly two-dozen amateur radio HF sources located in the midwestern United States was used to detect a enhancement in foF2 in that same region. We compare our results to those from other more conventional radio instruments and models of the ionosphere to demonstrate the scientific merit of incorporating amateur radio networks for radio science at HF.

  5. 75 FR 10439 - Cognitive Radio Technologies and Software Defined Radios

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-08

    ... Order 1. On March 17, 2005, the Commission adopted the Cognitive Radio Report and Order, 70 FR 23032... Memorandum Opinion and Order (MO&O), 72 FR 31190, June 6, 2007, which responded to two petitions filed in... COMMISSION 47 CFR Part 2 Cognitive Radio Technologies and Software Defined Radios AGENCY:...

  6. Talk Radio as Interpersonal Communication.

    ERIC Educational Resources Information Center

    Armstrong, Cameron B.; Rubin, Alan M.

    1989-01-01

    Examines whether talk radio serves different purposes for listeners who phone in, compared to those who do not. Finds that talk radio provides callers with an accessible and nonthreatening alternative to interpersonal communication. (MS)

  7. Prism beamswitch for radio telescopes.

    PubMed

    Payne, J M; Ulich, B L

    1978-12-01

    A dielectric prism and switching mechanism have been constructed for beamswitching a Cassegrain radio telescope. Spatially extended radio sources may be mapped without significant confusion utilizing the sensitivity and stability inherent in the conventional Dicke radiometer. PMID:18699031

  8. Torun Radio Astronomy Observatory

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Torun Center for Astronomy is located at Piwnice, 15 km north of Torun, Poland. A part of the Faculty of Physics and Astronomy of the Nicolaus Copernicus University, it was created by the union of Torun Radio Astronomy Observatory (TRAO) and the Institute of Astronomy on 1 January 1997....

  9. Albanian: Basic Radio Communications.

    ERIC Educational Resources Information Center

    Defense Language Inst., Washington, DC.

    This volume has been designed as a supplement to a course in Albanian developed by the Defense Language Institute. The emphasis in this text is placed on radio communications instruction. The volume is divided into five exercises, each of which contains a vocabulary, dictation, and an air-to-ground communications procedure conducted in Albanian…

  10. A Radio Station Project.

    ERIC Educational Resources Information Center

    Geva, Edna

    2002-01-01

    Describes a radio program in an English-as-a-Foreign-Language classroom in Israel. Classrooms of English students listen carefully to daily broadcasts, waiting to solve the brain teaser. Personal messages and catchy music follow the program. The project has encouraged students to use English actively and purposefully. Evaluation of the broadcasts…

  11. Radio Channel Simulator (RCSM)

    Energy Science and Technology Software Center (ESTSC)

    2007-01-31

    This is a simulation package for making site specific predictions of radio signal strength. The software computes received power at discrete grid points as a function of the transmitter location and propagation environment. It is intended for use with wireless network simulation packages and to support wireless network deployments.

  12. Svetloe Radio Astronomical Observatory

    NASA Technical Reports Server (NTRS)

    Smolentsev, Sergey; Rahimov, Ismail

    2013-01-01

    This report summarizes information about the Svetloe Radio Astronomical Observatory activities in 2012. Last year, a number of changes took place in the observatory to improve some technical characteristics and to upgrade some units to their required status. The report provides an overview of current geodetic VLBI activities and gives an outlook for the future.

  13. RADIO RANGING DEVICE

    DOEpatents

    Nieset, R.T.

    1961-05-16

    A radio ranging device is described. It utilizes a super regenerative detector-oscillator in which echoes of transmitted pulses are received in proper phase to reduce noise energy at a selected range and also at multiples of the selected range.

  14. Zelenchukskaya Radio Astronomical Observatory

    NASA Technical Reports Server (NTRS)

    Smolentsev, Sergey; Dyakov, Andrei

    2013-01-01

    This report summarizes information about Zelenchukskaya Radio Astronomical Observatory activities in 2012. Last year a number of changes took place in the observatory to improve some technical characteristics and to upgrade some units to the required status. The report provides an overview of current geodetic VLBI activities and gives an outlook for the future.

  15. Educational Broadcasting--Radio.

    ERIC Educational Resources Information Center

    Ahamed, Uvais; Grimmett, George

    This manual is intended for those who must conduct educational radio broadcasting training courses in Asia-Pacific countries without the resources of experienced personnel, as well as for individuals to use in self-learning situations. The selection of material has been influenced by the need to use broadcasting resources effectively in programs…

  16. Japanese Radio Exercises. Revised.

    ERIC Educational Resources Information Center

    Young, Jocelyn

    This unit focuses on Japanese radio exercises which became popular in Japan just after World War II and are still used among students and workers in companies to help raise morale and form group unity. The exercises reflect the general role of exercise in Japanese culture--to serve as a symbol of unity and cooperation among the Japanese, as well…

  17. Radio Is an Educational Medium.

    ERIC Educational Resources Information Center

    Duby, Aliza

    This report summarizes information found in a survey of the literature on radio as an educational medium which covered the published literature from many areas of the world. Comments on the literature reviewed are provided throughout the text, which is organized under seven major headings: (1) Radio, Mass Medium; (2) Radio, the Medium (broadening…

  18. Radio as a Teaching Tool.

    ERIC Educational Resources Information Center

    Thomson, Peggy

    1980-01-01

    National Public Radio's educational staff is experimenting with radio in the classroom by dramatizing the issues of the Afghan crisis in an audiodisc presentation mailed to teachers around the country. The article includes samples of dialogue from the tape, student opinions, and why radio is the medium used. (CT)

  19. Radio: Your Publics Are Listening!

    ERIC Educational Resources Information Center

    Marx, Gary

    The purpose of this booklet is to provide school board members, administrators, teachers, and others interested in education with an understanding of radio, how it works, and how school systems can take advantage of the communications possibilities offered by radio. After providing background information on radio as a mass communications medium…

  20. Ham Radio is Mir Magic.

    ERIC Educational Resources Information Center

    Evans, Gary

    1997-01-01

    Presents a classroom activity in which students communicated with U.S. and Russian astronauts via ham radio while they were in orbit on the space station Mir. Gives suggestions for other ham radio classroom activities as well as names of organizations, publications, and grant programs that teachers can access to help in bring ham radio into their…

  1. The LOFAR radio environment

    NASA Astrophysics Data System (ADS)

    Offringa, A. R.; de Bruyn, A. G.; Zaroubi, S.; van Diepen, G.; Martinez-Ruby, O.; Labropoulos, P.; Brentjens, M. A.; Ciardi, B.; Daiboo, S.; Harker, G.; Jelić, V.; Kazemi, S.; Koopmans, L. V. E.; Mellema, G.; Pandey, V. N.; Pizzo, R. F.; Schaye, J.; Vedantham, H.; Veligatla, V.; Wijnholds, S. J.; Yatawatta, S.; Zarka, P.; Alexov, A.; Anderson, J.; Asgekar, A.; Avruch, M.; Beck, R.; Bell, M.; Bell, M. R.; Bentum, M.; Bernardi, G.; Best, P.; Birzan, L.; Bonafede, A.; Breitling, F.; Broderick, J. W.; Brüggen, M.; Butcher, H.; Conway, J.; de Vos, M.; Dettmar, R. J.; Eisloeffel, J.; Falcke, H.; Fender, R.; Frieswijk, W.; Gerbers, M.; Griessmeier, J. M.; Gunst, A. W.; Hassall, T. E.; Heald, G.; Hessels, J.; Hoeft, M.; Horneffer, A.; Karastergiou, A.; Kondratiev, V.; Koopman, Y.; Kuniyoshi, M.; Kuper, G.; Maat, P.; Mann, G.; McKean, J.; Meulman, H.; Mevius, M.; Mol, J. D.; Nijboer, R.; Noordam, J.; Norden, M.; Paas, H.; Pandey, M.; Pizzo, R.; Polatidis, A.; Rafferty, D.; Rawlings, S.; Reich, W.; Röttgering, H. J. A.; Schoenmakers, A. P.; Sluman, J.; Smirnov, O.; Sobey, C.; Stappers, B.; Steinmetz, M.; Swinbank, J.; Tagger, M.; Tang, Y.; Tasse, C.; van Ardenne, A.; van Cappellen, W.; van Duin, A. P.; van Haarlem, M.; van Leeuwen, J.; van Weeren, R. J.; Vermeulen, R.; Vocks, C.; Wijers, R. A. M. J.; Wise, M.; Wucknitz, O.

    2013-01-01

    Aims: This paper discusses the spectral occupancy for performing radio astronomy with the Low-Frequency Array (LOFAR), with a focus on imaging observations. Methods: We have analysed the radio-frequency interference (RFI) situation in two 24-h surveys with Dutch LOFAR stations, covering 30-78 MHz with low-band antennas and 115-163 MHz with high-band antennas. This is a subset of the full frequency range of LOFAR. The surveys have been observed with a 0.76 kHz/1 s resolution. Results: We measured the RFI occupancy in the low and high frequency sets to be 1.8% and 3.2% respectively. These values are found to be representative values for the LOFAR radio environment. Between day and night, there is no significant difference in the radio environment. We find that lowering the current observational time and frequency resolutions of LOFAR results in a slight loss of flagging accuracy. At LOFAR's nominal resolution of 0.76 kHz and 1 s, the false-positives rate is about 0.5%. This rate increases approximately linearly when decreasing the data frequency resolution. Conclusions: Currently, by using an automated RFI detection strategy, the LOFAR radio environment poses no perceivable problems for sensitive observing. It remains to be seen if this is still true for very deep observations that integrate over tens of nights, but the situation looks promising. Reasons for the low impact of RFI are the high spectral and time resolution of LOFAR; accurate detection methods; strong filters and high receiver linearity; and the proximity of the antennas to the ground. We discuss some strategies that can be used once low-level RFI starts to become apparent. It is important that the frequency range of LOFAR remains free of broadband interference, such as DAB stations and windmills.

  2. Collaborative Beamfocusing Radio (COBRA)

    NASA Astrophysics Data System (ADS)

    Rode, Jeremy P.; Hsu, Mark J.; Smith, David; Husain, Anis

    2013-05-01

    A Ziva team has recently demonstrated a novel technique called Collaborative Beamfocusing Radios (COBRA) which enables an ad-hoc collection of distributed commercial off-the-shelf software defined radios to coherently align and beamform to a remote radio. COBRA promises to operate even in high multipath and non-line-of-sight environments as well as mobile applications without resorting to computationally expensive closed loop techniques that are currently unable to operate with significant movement. COBRA exploits two key technologies to achieve coherent beamforming. The first is Time Reversal (TR) which compensates for multipath and automatically discovers the optimal spatio-temporal matched filter to enable peak signal gains (up to 20 dB) and diffraction-limited focusing at the intended receiver in NLOS and severe multipath environments. The second is time-aligned buffering which enables TR to synchronize distributed transmitters into a collaborative array. This time alignment algorithm avoids causality violations through the use of reciprocal buffering. Preserving spatio-temporal reciprocity through the TR capture and retransmission process achieves coherent alignment across multiple radios at ~GHz carriers using only standard quartz-oscillators. COBRA has been demonstrated in the lab, aligning two off-the-shelf software defined radios over-the-air to an accuracy of better than 2 degrees of carrier alignment at 450 MHz. The COBRA algorithms are lightweight, with computation in 5 ms on a smartphone class microprocessor. COBRA also has low start-up latency, achieving high accuracy from a cold-start in 30 ms. The COBRA technique opens up a large number of new capabilities in communications, and electronic warfare including selective spatial jamming, geolocation and anti-geolocation.

  3. X-ray and radio core emission in radio quasars

    NASA Technical Reports Server (NTRS)

    Kembhavi, A.; Feigelson, E. D.; Singh, K. P.

    1986-01-01

    In order to investigate the physical relationship between X-ray and radio core emission in radio-selected quasars, 35 radio quasars have been observed with the VLA at 6 and 20 cm. The sample was chosen from a list of radio quasars with known X-ray luminosity but poorly known radio properties. Including data gathered from the literature, radio core detections or upper limits at 6 cm have been obtained for 127 radio quasars which have published Einstein X-ray data. A statistical association is sought between radio core luminosity and X-ray luminosity, and it is found that there is a strong correlation. The slope of the relation of L(x) to L(Gamma)-alpha is alpha = 0.71 + or - 0.07 for unresolved quasars with flat radio spectra. The slope decreases as quasars with extended radio regions are considered. This is traced to the presence of radio emission which is unrelated to the X-ray emission, in the presently unresolved cores of quasars.

  4. Accurate radio and optical positions for southern radio sources

    NASA Technical Reports Server (NTRS)

    Harvey, Bruce R.; Jauncey, David L.; White, Graeme L.; Nothnagel, Axel; Nicolson, George D.; Reynolds, John E.; Morabito, David D.; Bartel, Norbert

    1992-01-01

    Accurate radio positions with a precision of about 0.01 arcsec are reported for eight compact extragalactic radio sources south of -45-deg declination. The radio positions were determined using VLBI at 8.4 GHz on the 9589 km Tidbinbilla (Australia) to Hartebeesthoek (South Africa) baseline. The sources were selected from the Parkes Catalogue to be strong, flat-spectrum radio sources with bright optical QSO counterparts. Optical positions of the QSOs were also measured from the ESO B Sky Survey plates with respect to stars from the Perth 70 Catalogue, to an accuracy of about 0.19 arcsec rms. These radio and optical positions are as precise as any presently available in the far southern sky. A comparison of the radio and optical positions confirms the estimated optical position errors and shows that there is overall agreement at the 0.1-arcsec level between the radio and Perth 70 optical reference frames in the far south.

  5. Radio tomography of the ionosphere

    SciTech Connect

    Kunitsyn, V.E.; Tereshchenko, E.D. RAN, Poliarnyi Geofizicheskii Inst., Murmansk )

    1992-10-01

    This paper provides on overview of tomographic approaches to ionospheric remote sensing in the radio-wave range. The ionosphere has a very complicated structure. Thus, it is reasonable to divide tomographic methods into deterministic and statistical ones. The deterministic tomography problems can be subdivided into ray radio tomography and diffraction radio tomography. The statistical radio tomography approach is used when it is necessary to reconstruct the statistical structure of a great number of inhomogeneities, on the basis of measurements of field statistics (instead of one realization of the reconstruction of an inhomogeneity). The methods of solving radio-tomography problems, and their connection with inverse-scattering problems, are considered. The results of some first experiments are described, which show the possibilities of the radio tomography approaches. In conclusion, we discuss perspectives, directions of the development of radio tomography, and problems which appear. 30 refs.

  6. Compact radio cores in radio-quiet active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Maini, A.; Prandoni, I.; Norris, R. P.; Giovannini, G.; Spitler, L. R.

    2016-04-01

    Context. The mechanism of radio emission in radio-quiet (RQ) active galactic nuclei (AGNs) is still debated and might arise from the central AGN, from star formation activity in the host, or from either of these sources. A direct detection of compact and bright radio cores embedded in sources that are classified as RQ can unambiguously determine whether a central AGN significantly contributes to the radio emission. Aims: We search for compact, high-surface-brightness radio cores in RQ AGNs that are caused unambiguously by AGN activity. Methods: We used the Australian Long Baseline Array to search for compact radio cores in four RQ AGNs located in the Extended Chandra Deep Field South (ECDFS). We also targeted four radio-loud (RL) AGNs as a control sample. Results: We detected compact and bright radio cores in two AGNs that are classified as RQ and in one that is classified as RL. Two RL AGNs were not imaged because the quality of the observations was too poor. Conclusions: We report on a first direct evidence of radio cores in RQ AGNs at cosmological redshifts. Our detections show that some of the sources that are classified as RQ contain an active AGN that can contribute significantly (~50% or more) to the total radio emission.

  7. High stability radio links

    NASA Technical Reports Server (NTRS)

    Kursinski, E. Robert

    1989-01-01

    Radio telecommunication links are used for communication with deep space probes. These links consist of sinusoidal carrier signals at radio frequencies (RF) modulated with information sent between the spacecraft and the earth. This carrier signal is a very pure and stable sinusoid, typically derived from an atomic frequency standard whose frequency and phase are used to measure the radial velocity of the probe and from this and other data types derive its trajectory. This same observable can be used to search for space-time distortions cased by low frequency (0.1 to 100 MHz) gravitation radiation. How such a system works, what its sensitivity limitations are, and what potential future improvements can be made are discussed.

  8. Stellar radio emission

    NASA Technical Reports Server (NTRS)

    Bookbinder, Jay A.

    1988-01-01

    This paper presents an overview of the various radiation mechanisms believed to play a role in stellar radio emission. The radio emission from most stars is nonthermal and is generally due to mildly relativistic electrons with energies from a few keV to over 10 MeV. Magnetic fields play a crucial role both in accelerating the electrons to the requisite energies and in mediating the emission mechanism. They also play a fundamental role in creating the velocity anisotropies that are necessary for the operation of some of the coherent emission mechanisms. Coherent emission is seen most commonly on the M dwarfs, rarely on the RS CVns, and has yet to be detected for any other class of star. These coherent processes are best studied by means of their dynamic spectra; such studies are now just getting underway.

  9. [Radio-guided parathyroidectomy].

    PubMed

    Calbo, L; Gorgone, S; Palmieri, R; Lazzara, S; Sciglitano, P; Catalfamo, A; Calbo, E; Campennì, A; Ruggeri, M; Vermiglio, F; Baldari, S

    2009-01-01

    The Authors, after a careful review of literature about the instrumental diagnostic techniques (with particular attention to the nuclear-medical ones) and the surgical therapy of parathyroid diseases, report their experience on the use of the radio-guided mininvasive surgery with MIBI and gamma-probe for intraoperative localization of pathological glands. Once exposed their experience, the Authors conclude asserting that this technique is fast, slightly invasive and expensive, and certainly useful for the detection of pathological or ectopic glands. It can be widely employed because, in comparison to its numerous advantages, such as the reduction of the operating time and of the hospital-stay, the greater radicality and the possibility to use mininvasive techniques, it does not present significant technical limitations and/or radio-protectionistic problems. PMID:20109383

  10. Mobile radio - An overview

    NASA Astrophysics Data System (ADS)

    Kucar, Andy D.

    1991-11-01

    Following a brief prologue and historical overview, such technical issues as the repertoire of systems and services, management of the airwaves, the operating environment, service quality, network issues and cell size, channel coding and modulation, speech coding, diversity, multiplex, and multiple access (FDMA, TDMA, CDMA) are discussed. Also addressed are the potential economic and sociological impacts of mobile radio communications in the wake of the redistribution of airwaves at the World Administrative Radio Conference WARC '92. Performance dependence on multipath delay (related to the cell size and terrain configuration), Doppler frequency (related to the carrier frequency, data rate, and the speed of vehicles), and message length (can dictate the choice of multiple access) is briefly discussed.

  11. Rosetta Radio Science Investigations

    NASA Technical Reports Server (NTRS)

    Patzold, M.; Neubauer, F. M.; Wennmacher, A.; Aksnes, K.; Anderson, J. D.; Asmar, S. W.; Tinto, M.; Tsurutani, B. T.; Yeomans, D. K.; Barriot, J. -P.; Bird, M. K.; Boehnhardt, H.; Gill, E.; Montenbruck, O.; Grun, E.; Hausler, B.; Ip, W. H.; Thomas, N.; Marouf, E. A.; Rickman, H.; Wallis, M. K.; Wickramasinghe, N. C.

    1996-01-01

    The Rosetta Radio Science Investigations (RSI) experiment was selected by the European Space Agency to be included in the International Rosetta Mission to comet P/Wirtanen (launch in 2003, arrival and operational phase at the comet 2011-2013). The RSI science objectives address fundamental aspects of cometary physics such as the mass and bulk density of the nucleus, the gravity field, non-gravitational forces, the size and shape, the internal structure, the composition and roughness of the nucleus surface, the abundance of large dust grains and the plasma content in the coma and the combined dust and gas mass flux on the orbiter. RSI will make use of the radio system of the Rosetta spacecraft.

  12. Workshop on Radio Transients

    NASA Astrophysics Data System (ADS)

    Croft, Steve; Gaensler, Bryan

    2012-04-01

    abstract-type="normal">SummaryWe are entering a new era in the study of variable and transient radio sources. This workshop discussed the instruments and the strategies employed to study those sources, how they are identified and classified, how results from different surveys can be compared, and how radio observations tie in with those at other wavelengths. The emphasis was on learning what common ground there is between the plethora of on-going projects, how methods and code can be shared, and how best practices regarding survey strategy could be adopted. The workshop featured the four topics below. Each topic commenced with a fairly brief introductory talk, which then developed into discussion. By way of preparation, participants had been invited to upload and discuss one slide per topic to a wiki ahead of the workshop. 1. Telescopes, instrumentation and survey strategy. New radio facilities and on-going projects (including upgrades) are both studying the variability of the radio sky, and searching for transients. The discussion first centred on the status of those facilities, and on projects with a time-domain focus, both ongoing and planned, before turning to factors driving choices of instrumentation, such as phased array versus single pixel feeds, the field of view, spatial and time resolution, frequency and bandwidth, depth, area, and cadence of the surveys. 2. Detection, pipelines, and classification. The workshop debated (a) the factors that influence decisions to study variability in the (u,v) plane, in images, or in catalogues, (b) whether, and how much, pipeline code could potentially be shared between one project and another, and which software packages are best for different approaches, (c) how data are stored and later accessed, and (d) how transients and variables are defined and classified. 3. Statistics, interpretation, and synthesis. It then discussed how (i) the choice of facility and strategy and (ii) detection and classification schemes

  13. Radio quiet, please! - protecting radio astronomy from interference

    NASA Astrophysics Data System (ADS)

    van Driel, W.

    2011-06-01

    The radio spectrum is a finite and increasingly precious resource for astronomical research, as well as for other spectrum users. Keeping the frequency bands used for radio astronomy as free as possible of unwanted Radio Frequency Interference (RFI) is crucial. The aim of spectrum management, one of the tools used towards achieving this goal, includes setting regulatory limits on RFI levels emitted by other spectrum users into the radio astronomy frequency bands. This involves discussions with regulatory bodies and other spectrum users at several levels - national, regional and worldwide. The global framework for spectrum management is set by the Radio Regulations of the International Telecommunication Union, which has defined that interference is detrimental to radio astronomy if it increases the uncertainty of a measurement by 10%. The Radio Regulations are revised every three to four years, a process in which four organisations representing the interests of the radio astronomical community in matters of spectrum management (IUCAF, CORF, CRAF and RAFCAP) participate actively. The current interests and activities of these four organisations range from preserving what has been achieved through regulatory measures, to looking far into the future of high frequency use and giant radio telescope use.

  14. Radio jets in NGC 4151

    NASA Technical Reports Server (NTRS)

    Johnston, K. J.; Elvis, M.; Kjer, D.; Shen, B. S. P.

    1982-01-01

    The relationship between the radio and optical emissions from the nucleus of the Seyfert galaxy NGC 4151 is investigated by mapping the radio radiation from this source at wavelengths of 20 and 6 cm using the Very Large Array of the National Radio Astronomy Observatory. Results show that the radio emission at wavelengths from 20 to 6 cm extend 10'' (950 pc) along a position angle of 72-84 degrees. This nonthermal emission is found to consist of at least six components and is similar to jets observed in other compact extragalactic radio sources. These radio jets appear to be coincident with the optical line emission region in NGC 4151 and are aligned with the position angle of the linearly polarized optical continuum emission.

  15. Locating Radio Noise from Sprites

    NASA Astrophysics Data System (ADS)

    Fullekrug, M.; Mezentsev, A.; Watson, R.; Gaffet, S.; Astin, I.; Evans, A.

    2014-12-01

    Sprites are composed of individual streamer discharges (e.g., Pasko, 2010) which split into exponentially growing streamer tips (McHarg et al., 2010). The acceleration of the electrons to a few eV results in the radiation of a small amount of electromagnetic energy. The incoherent superposition of many streamers causes the low frequency radio noise from sprites near ~40 km height (Qin et al., 2012). The presence of this theoretically predicted radiation was recently confirmed by low frequency radio noise measurements during dancing sprites with a very sensitive radio receiver (Fullekrug et al., 2013). To locate the radio noise from sprites in the sky, an interferometric network of low frequency radio receivers was developed (Mezentsev and Fullekrug, JGR, 2013). The key parameter for the interferometric signal processing is the frequency dependent wave propagation velocity of the radio waves within the Earth's atmosphere. This wave propagation velocity is determined by the wave number vector which needs to be inferred from the measurements. Here we adapt and subsequently apply array analyses which have been developed for seismic and infrasound arrays to determine the horizontal wave number vectors of ~20-24 kHz radio waves measured with an array of ten radio receivers distributed over an area of ~1 km × 1 km. It is found that the horizontal slowness of ~20-24 kHz radio waves ranges from ~2.7 ns/m to ~4.1 ns/m depending on the arrival azimuth of the radio wave. For comparison, an electromagnetic wave in vacuum has a slowness of ~3.34 ns/m. A larger slowness indicates an apparent velocity which is smaller than the speed of light and a smaller slowness indicates that the radio wave arrives at the array from an elevation angle. The observed variability of the observed slowness almost certainly results from the distance dependent superposition of the transverse electric and magnetic TEn and TMn radio wave propagation modes.

  16. Decimetric radio dot emissions

    NASA Astrophysics Data System (ADS)

    Mészárosová, H.; Karlický, M.; Sawant, H. S.; Fernandes, F. C. R.; Cecatto, J. R.; de Andrade, M. C.

    2008-11-01

    Context: We study a rare type of solar radio bursts called decimetric dot emissions. Aims: In the period 1999-2001, 20 events of decimetric dot emissions observed by the Brazilian Solar Spectroscope (BSS) in the frequency range 950-2640 MHz are investigated statistically and compared with radio fine structures of zebras and fibers. Methods: For the study of the spectral characteristics of the dot emissions we use specially developed Interactive Data Language (IDL) software called BSSView and basic statistical methods. Results: We have found that the dm dot emissions, contrary to the fine structures of the type IV bursts (i.e. zebras, fibers, lace bursts, spikes), are not superimposed on any background burst emission. In the radio spectrum, in most cases the dot emissions form chains that appear to be arranged in zebra patterns or fibers. Because some zebras and fibers, especially those observed with high time and high spectral resolutions, also show emission dots (but superimposed on the background burst emission), we compared the spectral parameters of the dot emissions with the dots being the fine structure of zebras and fibers. For both these dots, similar spectral characteristics were found. Some similarities of the dot emissions can be found also with the lace bursts and spikes. For some events the dot emissions show structural evolution from patterns resembling fibers to patterns resembling zebras and vice versa, or they evolve into fully chaotic patterns. Conclusions: For the first time, we present decimetric dot emissions that appear to be arranged in zebra patterns or fibers. We propose that these emissions are generated by the plasma emission mechanism at the locations in the solar atmosphere where the double resonance condition is fulfilled.

  17. Internet Resources for Radio Astronomy

    NASA Astrophysics Data System (ADS)

    Andernach, H.

    A subjective overview of Internet resources for radio-astronomical information is presented. Basic observing techniques and their implications for the interpretation of publicly available radio data are described, followed by a discussion of existing radio surveys, their level of optical identification, and nomenclature of radio sources. Various collections of source catalogues and databases for integrated radio source parameters are reviewed and compared, as well as the web interfaces to interrogate the current and ongoing large-area surveys. Links to radio observatories with archives of raw (uv-) data are presented, as well as services providing images, both of individual objects or extracts (``cutouts'') from large-scale surveys. While the emphasis is on radio continuum data, a brief list of sites providing spectral line data, and atomic or molecular information is included. The major radio telescopes and surveys under construction or planning are outlined. A summary is given of a search for previously unknown optically bright radio sources, as performed by the students as an exercise, using Internet resources only. Over 200 different links are mentioned and were verified, but despite the attempt to make this report up-to-date, it can only provide a snapshot of the situation as of mid-1998.

  18. Observations of Solar Radio Transients

    NASA Astrophysics Data System (ADS)

    Paige, Giorla

    2011-05-01

    A low frequency radio telescope has been recently been constructed on the campus of the The College of New Jersey (TCNJ) and has begun conducting observations at 20MHz as part of NASA'a Radio Jove program. This instrument is capable of observations of solar radio emission including strong prompt radio emission associated with solar burst events. We will discuss solar observations conducted with this instrument as well as an effort to conduct coincident observations with the Eight-meter-wavelength Transient Array (ETA) and the Long Wavelength Array (LWA).

  19. Circumstellar radio molecular lines

    NASA Technical Reports Server (NTRS)

    NGUYEN-QUANG-RIEU

    1987-01-01

    Radio molecular lines appear to be useful probes into the stellar environment. Silicon oxide masers provide information on the physical conditions in the immediate vicinity of the stellar photosphere. Valuable information on the physics operating in the envelope of IRC + 10216 was recently obtained by high sensitivity observations and detailed theoretical analyses. Infrared speckle interferometry in the molecular lines and in the continuum is helpful in the investigation of the inner region of the envelope. These techniques are discussed in terms of late-type star mass loss.

  20. Solar radio emission

    NASA Technical Reports Server (NTRS)

    Goldman, M. V.; Smith, D. F.

    1981-01-01

    Active areas of both observational and theoretical research in which rapid progress is being made are discussed. These include: (1) the dynamic spectrum or frequency versus time plot; (2) physical mechanisms in the development of various types of bursts; (3) microwave type 1, 2, 3, and moving type 4 bursts; (4) bursts caused by trapped electrons; (5) physics of type 3bursts; (6) the physics of type 2 bursts and their related shocks; (7) the physics of both stationary and moving traps and associated type 1 and moving type 4 bursts; and (8) the status of the field of solar radio emission.

  1. RADIO FREQUENCY ATTENUATOR

    DOEpatents

    Giordano, S.

    1963-11-12

    A high peak power level r-f attenuator that is readily and easily insertable along a coaxial cable having an inner conductor and an outer annular conductor without breaking the ends thereof is presented. Spaced first and second flares in the outer conductor face each other with a slidable cylindrical outer conductor portion therebetween. Dielectric means, such as water, contact the cable between the flares to attenuate the radio-frequency energy received thereby. The cylindrical outer conductor portion is slidable to adjust the voltage standing wave ratio to a low level, and one of the flares is slidable to adjust the attenuation level. An integral dielectric container is also provided. (AFC)

  2. Educational Radio: A Review of the Literature.

    ERIC Educational Resources Information Center

    Grise, Philip J., Jr.; And Others

    Radio has been used for educational purposes since its beginning in the early 1920's; the application of radio to the educational problems of the developing nations is not a new concept by any means. Among the uses of educational radio are foreign radio schools, classroom radio uses, "Accion Cultural Popular" (ACPO), and correspondence radio…

  3. The Extragalactic Radio Background

    NASA Technical Reports Server (NTRS)

    Kogut, A.; Fixsen, D. J.; Levin, S. M.; Limon, M.; Lubin, P. M.; Seiffert, M.; Singal, J.; Villela, T.; Wollack, E.; Wuensche, C. A.

    2011-01-01

    The existence of an isotropic component of the high-latitude radio sky has been recognized for nearly fifty years, but has typically been assumed to be Galactic in origin. We use recent radio observations to test whether the observed high-latitude component could originate within either an extended Galactic halo or a more local "bubble" structure. The lack of significant polarization from the isotropic component, combined with the lack of significant correlation with the Galactic far-infrared emission, rule out an origin within the Galaxy. We conclude that an extragalactic origin is the only viable alternative for the bulk of the isotropic high-latitude emission. The extragalactic component is 2-3 times brighter than local (Galactic) emission towards the Galactic poles and is consistent with a power law in frequency with amplitude T(sub r) = 24.1 plus or minus 2.1 K and spectral index beta = -2.599 plus or minus 0.036 evaluated at reference frequency 310 MHz.

  4. Angular momentum radio

    NASA Astrophysics Data System (ADS)

    Thidé, B.; Tamburini, F.; Then, H.; Someda, C. G.; Mari, Elletra; Parisi, G.; Spinello, F.; Romanato, Fra

    2014-02-01

    Wireless communication amounts to encoding information onto physical observables carried by electromagnetic (EM) fields, radiating them into surrounding space, and detecting them remotely by an appropriate sensor connected to an informationdecoding receiver. Each observable is second order in the fields and fulfills a conservation law. In present-day radio only the EM linear momentum observable is fully exploited. A fundamental physical limitation of this observable, which represents the translational degrees of freedom of the charges (typically an oscillating current along a linear antenna) and the fields, is that it is single-mode. This means that a linear-momentum radio communication link comprising one transmitting and one receiving antenna, known as a single-input-single-output (SISO) link, can provide only one transmission channel per frequency (and polarization). In contrast, angular momentum, which represents the rotational degrees of freedom, is multi-mode, allowing an angular-momentum SISO link to accommodate an arbitrary number of independent transmission channels on one and the same frequency (and polarization). We describe the physical properties of EM angular momentum and how they can be exploited, discuss real-world experiments, and outline how the capacity of angular momentum links may be further enhanced by employing multi-port techniques, i.e., the angular momentum counterpart of linear-momentum multiple-input-multiple-output (MIMO).

  5. Looking for radio waves with a simple radio wave detector

    NASA Astrophysics Data System (ADS)

    Sugimoto (Stray Cats), Norihiro

    2011-11-01

    I created a simple device that can detect radio waves in a classroom. In physics classes I tell students that we live in a sea of radio waves. They come from TV, radio, and cell phone signals as well as other sources. Students don't realize this because those electromagnetic waves are invisible. So, I wondered if I could come up with a way to detect the waves and help students to understand them better. Electromagnetic wave meters, which measure intensity of radio waves quantitatively, are commercially available. However, to students most of these are black boxes, and at the introductory level it is more effective to detect radio waves in a simpler way. This paper describes my device and how I have used it in my classes.

  6. Space Telecommunications Radio Architecture (STRS)

    NASA Technical Reports Server (NTRS)

    Reinhart, Richard C.

    2006-01-01

    A software defined radio (SDR) architecture used in space-based platforms proposes to standardize certain aspects of radio development such as interface definitions, functional control and execution, and application software and firmware development. NASA has charted a team to develop an open software defined radio hardware and software architecture to support NASA missions and determine the viability of an Agency-wide Standard. A draft concept of the proposed standard has been released and discussed among organizations in the SDR community. Appropriate leveraging of the JTRS SCA, OMG's SWRadio Architecture and other aspects are considered. A standard radio architecture offers potential value by employing common waveform software instantiation, operation, testing and software maintenance. While software defined radios offer greater flexibility, they also poses challenges to the radio development for the space environment in terms of size, mass and power consumption and available technology. An SDR architecture for space must recognize and address the constraints of space flight hardware, and systems along with flight heritage and culture. NASA is actively participating in the development of technology and standards related to software defined radios. As NASA considers a standard radio architecture for space communications, input and coordination from government agencies, the industry, academia, and standards bodies is key to a successful architecture. The unique aspects of space require thorough investigation of relevant terrestrial technologies properly adapted to space. The talk will describe NASA s current effort to investigate SDR applications to space missions and a brief overview of a candidate architecture under consideration for space based platforms.

  7. SETI radio spectrum surveillance system

    NASA Technical Reports Server (NTRS)

    Crow, B.; Lokshin, A.; Marina, M.; Ching, L.

    1985-01-01

    The SETI Radio Spectrum Surveillance System (SRSSS) will provide a data base for assessing the radio frequency interference (RFI) environment for SETI and minimizing RFI disruptions during the search. The system's hardware and software are described and the sensitivity of the system is discussed.

  8. The future for radio astronomy

    NASA Astrophysics Data System (ADS)

    Breton, Rene P.; Hassall, Tom

    2013-12-01

    THE TRANSIENT UNIVERSE Rene P Breton and Tom Hassall argue that, while radio astronomy has always involved transient phenomena, exploration of this part of the electromagnetic spectrum has been falling behind because of the lack of data. But the advent of a new generation of radio telescopes such as LOFAR, could change that.

  9. Frequency Allocation; The Radio Spectrum.

    ERIC Educational Resources Information Center

    Federal Communications Commission, Washington, DC.

    The Federal Communications Commission (FCC) assigns segments of the radio spectrum to categories of users, and specific frequencies within each segment to individual users. Since demand for channel space exceeds supply, the process is complex. The radio spectrum can be compared to a long ruler: the portion from 10-540 kiloHertz has been set aside…

  10. Stabilized radio-frequency quadrupole

    DOEpatents

    Lancaster, H.D.; Fugitt, J.A.; Howard, D.R.

    1982-09-29

    A long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator.

  11. Audiences for Contemporary Radio Formats.

    ERIC Educational Resources Information Center

    Lull, James T.; And Others

    A radio audience survey of 110 sample geographic clusters in the Santa Barbara, California, area served a twofold purpose: the construction of a demographic profile of audience types according to radio format choices, and the identification and analysis of various audience subgroups. A skip interval technique of these geographic clusters resulted…

  12. Radio outburst of BL Lacertae

    NASA Astrophysics Data System (ADS)

    Buemi, C. S.; Leto, P.; Trigilio, C.; Umana, G.; Giroletti, M.; Orienti, M.; Raiteri, C. M.; Villata, M.; Bach, U.

    2013-04-01

    We report on extremely high radio flux of BL Lacertae at 43 and 8 GHz. Observations at 43 GHz with the 32 m radio telescope in Noto (Italy) revealed a flux density of 10.5 +/- 0.2 Jy on 2013 April 10.65, while observations at 8 GHz with the 32 m radio telescope in Medicina (Italy) detected a flux density of 8.2 +/- 0.7 Jy on April 12.22. These extremely high radio fluxes show that the radio activity likely correlated to the strong optical, near-infrared, and gamma-ray activity of 2011-2012 (see ATels #4028, #4031, #4155, #4271, #4277, #4349, #4565, #4600), and X-ray activity of late 2012 (ATels #4557, #4627), is far to be exhausted.

  13. Planetary radio astronomy from Voyager

    NASA Technical Reports Server (NTRS)

    Alexander, J. K.

    1983-01-01

    The technique of radio astronomy makes it possible for a remote observer to detect the presence of magnetic fields and plasmas in planetary environments. Prior to the flights of the Voyager spacecraft, radio astronomical studies of Jupiter from earth and from earth orbit had correctly predicted the strength and orientation of Jupiter's magnetic field and trapped radiation belts. The Voyager Planetary Radio Astronomy investigations have now provided measurements of the complete spectrum of low frequency radio emissions from both planets. Each Voyager instrument consists of a pair of orthogonal, 10-m, electric monopole antennas which are connected to a step-tuned, superheterodyne receiver operating over the frequency range from 1.2 kHz to 40.5 MHz. The Voyager trajectory provided observations from above both the sunlit and nightside hemispheres of Jupiter. Saturn's nonthermal radio emission has been observed at frequencies as low as 3 kHz and as high as 1.2 MHz.

  14. CONSTRAINING RADIO EMISSION FROM MAGNETARS

    SciTech Connect

    Lazarus, P.; Kaspi, V. M.; Dib, R.; Champion, D. J.; Hessels, J. W. T.

    2012-01-10

    We report on radio observations of five magnetars and two magnetar candidates carried out at 1950 MHz with the Green Bank Telescope in 2006-2007. The data from these observations were searched for periodic emission and bright single pulses. Also, monitoring observations of magnetar 4U 0142+61 following its 2006 X-ray bursts were obtained. No radio emission was detected for any of our targets. The non-detections allow us to place luminosity upper limits of L{sub 1950} {approx}< 1.60 mJy kpc{sup 2} for periodic emission and L{sub 1950,single} {approx}< 7.6 Jy kpc{sup 2} for single pulse emission. These are the most stringent limits yet for the magnetars observed. The resulting luminosity upper limits together with previous results are discussed, as is the importance of further radio observations of radio-loud and radio-quiet magnetars.

  15. Radio-Optical Alignments in a Low Radio Luminosity Sample

    NASA Technical Reports Server (NTRS)

    Lacy, Mark; Ridgway, Susan E.; Wold, Margrethe; Lilje, Per B.; Rawlings, Steve

    1999-01-01

    We present an optically-based study of the alignment between the radio axes and the optical major axes of eight z approximately 0.7 radio galaxies in a 7C sample. The radio galaxies in this sample are approximately 20-times less radio luminous than 3C galaxies at the same redshift, and are significantly less radio-luminous than any other well-defined samples studied to date. Using Nordic Optical Telescope images taken in good seeing conditions at rest-frame wavelengths just longward of the 4000A break, we find a statistically significant alignment effect in the 7C sample. Furthermore, in two cases where the aligned components are well separated from the host we have been able to confirm spectroscopically that they are indeed at the same redshift as the radio galaxy. However, a quantitative analysis of the alignment in this sample and in a corresponding 3C sample from HST (Hubble Space Telescope) archival data indicates that the percentage of aligned flux may be lower and of smaller spatial scale in the 7C sample. Our study suggests that alignments on the 50-kpc scale are probably closely related to the radio luminosity, whereas those on the 15 kpc scale are not. We discuss these results in the context of popular models for the alignment effect.

  16. On the origin of radio emission in radio quiet quasars

    NASA Astrophysics Data System (ADS)

    Laor, Ari; Behar, Ehud

    The radio emission in radio loud quasars (RLQs) originates in a jet carrying relativistic electrons. In radio quiet quasars (RQQs) the radio emission is ˜ 103 times weaker, relative to other bands. Its origin is not clearly established yet, but it is often speculated to arise from a weak jet. Here we show that there is a tight relation between L_R and L_X for RQQs, with L_R/L_X˜ 10-5, based on the optically selected Palomar-Green (PG) quasars, with nearly complete X-ray and radio detections (avoiding biases and selection effects). Coronally active stars also show a tight relation between L_R and L_X with L_R/L_X˜ 10-5 (the Güdel & Benz relation), which together with correlated variability indicates that stellar coronae are magnetically heated. The X-ray emission of quasars most likely originates from a hot accretion disk corona, and since RQQs follow the Güdel & Benz relation, it is natural to associate their radio emission with coronal emission as well. The tight relation between L_R and L_X may simply reflect the equality of accretion disk coronal heating by magnetically generated relativistic electrons (producing L_R), and coronal cooling by Compton scattering (producing L_X). This suggestion can be tested by looking for correlated X-ray and radio variability patterns, such as the Neupert effect, displayed by stellar coronae.

  17. Radio pulsar disk electrodynamics

    NASA Technical Reports Server (NTRS)

    Michel, F. C.

    1983-01-01

    Macroscopic physics are discussed for the case of a disk close to an isolated, magnetized, rotating neutron star that acts as a Faraday disk dynamo, while the disk acts as both a load and a neutral sheet. This sheet allows the polar cap current to return to the neutron star, splitting a dipolar field into two monopolar halves. The dominant energy loss is from the stellar wind torque, and the next contribution is dissipation in the auroral zones, where the current returns to the star in a 5 cm-thick sheet. The disk itself may be a source of visible radiation comparable to that in pulsed radio frequency emission. As the pulsar ages, the disk expands and narrows into a ring which, it is suggested, may lead to a cessation of pulsed emission at periods of a few sec.

  18. Division X: Radio Astronomy

    NASA Astrophysics Data System (ADS)

    Nan, Ren-Dong; Taylor, Russ; Rodriguez, Luis F.; Chapman, Jessica; Dubner, Gloria; Garrett, Michael; Goss, W. Miller; Torrelles, Jose M.; Hirabayashi, Hisashi; Carilli, Chris; Hills, Richard; Shastri, Prajval

    2010-05-01

    The business meeting of Division X in the IAU 2009GA took place in three sessions during the day of August 6, 2009. The meeting, being well attended, started with the approval for the meeting agenda. Then the triennium reports were made in the first session by the president of Division X, Ren-Dong Nan, and by the chairs of three working groups: “Historic Radio Astronomy WG” by Wayne Orchiston, “Astrophysically Important Lines WG” by Masatoshi Ohishi, and “Global VLBI WG” by Tasso Tzioumis (proxy chair appointed by Steven Tingay). Afterwards, a dozen reports from observatories and worldwide significant projects have been presented in the second session. Business meeting of “Interference Mitigation WG” was located in the third session.

  19. Extragalactic radio sources

    NASA Technical Reports Server (NTRS)

    Sturrock, P. A.

    1984-01-01

    The standard model for extragalactic variable radio sources comprises an isotropically expanding plasmoid with frozen magnetic flux and an electron distribution which evolves adiabatically. This model leads to the following relaton between the peak luminosity L (sub nu, m) and the relevant frequency nu(sub m) which are functions of time: L(sub nu,m) is proportional to nu(sub m)(n) where N = (7n + 5)/(4n + 5). In this expression, n is the spectral index in the optically thin part of the spectrum, where L (sub nu) is proportional to nu (-n). For n in the range 0.5 to 1.5, the standard model yields N in the range 1.2 to 1.4. By contrast, analysis of observational data yields estimates of N in a small range about the mean value 0.4, in clear contradiction with the standard model.

  20. Radio Seeing Monitor Interferometer

    NASA Astrophysics Data System (ADS)

    Hiriart, David; Valdez, Jorge; Zaca, Placido; Medina, José L.

    2002-10-01

    A two-element interferometer for monitoring atmospheric phase fluctuations (radio seeing) is presented; this uses the unmodulated beacon signal at 11.715 GHz from a geostationary satellite. The system measures phase differences on the signal received by two small antennas separated by 50 m. The system incorporates the best features from previous designs: a heterodyne phase-lock receiver and an IQ demodulator system. Phase fluctuations measured at this frequency may be extrapolated to millimetric and submillimetric wavelengths since the atmosphere is not dispersive at these frequencies. The instrument has been tested at the Observatory San Pedro Martir (Mexico) at 2800 m above sea level. The final destination of the instrument is Cerro la Negra (Mexico), where the Large Millimeter Telescope is under construction, at an altitude of 4600 m.

  1. Radio frequency coaxial feedthrough

    DOEpatents

    Owens, Thomas L.

    1989-01-17

    An improved radio frequency coaxial transmission line vacuum feed-through provided based on the use of a half-wavelength annular dielectric pressure barrier disk, or multiple disks comprising an effective half wavelength structure to eliminate reflections from the barrier surfaces. Gas-tight seals are formed about the outer and inner diameter surfaces of the barrier disk using a sealing technique which generates radial forces sufficient to form seals by forcing the conductor walls against the surfaces of the barrier disks in a manner which does not deform the radii of the inner and outer conductors, thereby preventing enhancement of the electric field at the barrier faces which limits voltage and power handling capabilities of a feedthrough.

  2. Global Ionosphere Radio Observatory

    NASA Astrophysics Data System (ADS)

    Galkin, I. A.; Reinisch, B. W.; Huang, X. A.

    2014-12-01

    The Global Ionosphere Radio Observatory (GIRO) comprises a network of ground-based high-frequency vertical sounding sensors, ionosondes, with instrument installations in 27 countries and a central Lowell GIRO Data Center (LGDC) for data acquisition and assimilation, including 46 real-time data streams as of August 2014. The LGDC implemented a suite of technologies for post-processing, modeling, analysis, and dissemination of the acquired and derived data products, including: (1) IRI-based Real-time Assimilative Model, "IRTAM", that builds and publishes every 15-minutes an updated "global weather" map of the peak density and height in the ionosphere, as well as a map of deviations from the classic IRI climate; (2) Global Assimilative Model of Bottomside Ionosphere Timelines (GAMBIT) Database and Explorer holding 15 years worth of IRTAM computed maps at 15 minute cadence;. (3) 17+ million ionograms and matching ionogram-derived records of URSI-standard ionospheric characteristics and vertical profiles of electron density; (4) 10+ million records of the Doppler Skymaps showing spatial distributions over the GIRO locations and plasma drifts; (5) Data and software for Traveling Ionospheric Disturbance (TID) diagnostics; and (6) HR2006 ray tracing software mated to the "realistic" IRTAM ionosphere. In cooperation with the URSI Ionosonde Network Advisory Group (INAG), the LGDC promotes cooperative agreements with the ionosonde observatories of the world to accept and process real-time data of HF radio monitoring of the ionosphere, and to promote a variety of investigations that benefit from the global-scale, prompt, detailed, and accurate descriptions of the ionospheric variability.

  3. Teaching radio astronomy with Affordable Small Radio Telescope (ASRT)

    NASA Astrophysics Data System (ADS)

    Joshi, Bhal Chandra

    A simple, easy to build and portable radio telescope, called Affordable Small Radio Telescope (ASRT), has been developed by the Radio Physics Laboratory (RPL), a radio astronomy teaching unit associated with the National Centre for Radio Astrophysics (TIFR) and Inter-University Centre for Astronomy and Astrophysics (IUCAA), which are two premier astronomy institutes in India. ASRT consists of off-the-shelf available Direct to Home television dishes and is easy to assemble. Our design is scalable from simple very low cost telescope to more complex yet moderately costing instrument. ASRT provides a platform for demonstrating radio physics concepts through simple hands-on experiment as well as for carrying out solar monitoring by college/University students. The presentation will highlight the concept of ASRT and the different experiments that can be carried out using it. The solar monitoring observations will be discussed along-with details of methods for calibrating these measurements. The pedagogical usefulness of ASRT in introducing undergraduatephysics students to astrophysics, measurements and analysis methods used in radio astronomy will also be discussed. Use of ASRT in the last three years in the programs of RPL, namely the annual Radio Astronomy Winter School for College students (RAWSC) and Pulsar Observing for Students (POS) is also presented. This year a new program was initiated to form a virtual group of an ASRT community, which will not only share their measurements, but also think of improving the pedagogical usefulness of ASRT by innovative experiments. This initiative is presented with the best practices drawn from our experience in using ASRT as a tool for student training in space sciences. The talk will also point out future ideas in involving a larger body of students in simple radio astronomy experiments with the ASRT, which RPL is likely to nucleate as part of its mandate.

  4. Quasar emission lines, radio structures and radio unification

    NASA Astrophysics Data System (ADS)

    Jackson, Neal; Browne, I. W. A.

    2013-02-01

    Unified schemes of radio sources, which account for different types of radio active galactic nucleus in terms of anisotropic radio and optical emission, together with different orientations of the ejection axis to the line of sight, have been invoked for many years. Recently, large samples of optical quasars, mainly from the Sloan Digital Sky Survey (SDSS), together with large radio samples, such as Faint Images of the Radio Sky at Twenty cm (FIRST), have become available. These hold the promise of providing more stringent tests of unified schemes but, compared to previous samples, lack high-resolution radio maps. Nevertheless, they have been used to investigate unified schemes, in some cases yielding results which appear inconsistent with such theories. Here we investigate using simulations how the selection effects to which such investigations are subject can influence the conclusions drawn. In particular, we find that the effects of limited resolution do not allow core-dominated radio sources to be fully represented in the samples, that the effects of limited sensitivity systematically exclude some classes of sources and the lack of deep radio data make it difficult to decide to what extent closely separated radio sources are associated. Nevertheless, we conclude that relativistic unified schemes are entirely compatible with the current observational data. For a sample selected from SDSS and FIRST which includes weak-cored triples we find that the equivalent width of the [O III] emission line decreases as core dominance increases, as expected, and also that core-dominated quasars are optically brighter than weak-cored quasars.

  5. Radio Astronomy Explorer /RAE/. I - Observations of terrestrial radio noise.

    NASA Technical Reports Server (NTRS)

    Herman, J. R.; Caruso, J. A.; Stone, R. G.

    1973-01-01

    Radio Astronomy Explorer (RAE) I data are analyzed to establish characteristics of HF terrestrial radio noise at an altitude of about 6000 km. Time and frequency variations in amplitude of the observed noise well above cosmic noise background are explained on the basis of temporal and spatial variations in ionospheric critical frequency coupled with those in noise source distributions. It is shown that terrestrial radio noise regularly breaks through the ionosphere and reaches RAE with magnitudes 15 dB and more above cosmic noise background, on frequencies above the F-layer critical frequency.

  6. Radio Loud AGNs are Mergers

    NASA Astrophysics Data System (ADS)

    Chiaberge, Marco; Gilli, Roberto; Lotz, Jennifer M.; Norman, Colin

    2015-06-01

    We measure the merger fraction of Type 2 radio-loud and radio-quiet active galactic nuclei (AGNs) at z\\gt 1 using new samples. The objects have Hubble Space Telescope (HST) images taken with Wide Field Camera 3 (WFC3) in the IR channel. These samples are compared to the 3CR sample of radio galaxies at z\\gt 1 and to a sample of non-active galaxies. We also consider lower redshift radio galaxies with HST observations and previous generation instruments (NICMOS and WFPC2). The full sample spans an unprecedented range in both redshift and AGN luminosity. We perform statistical tests to determine whether the different samples are differently associated with mergers. We find that all (92%-14%+8%) radio-loud galaxies at z\\gt 1 are associated with recent or ongoing merger events. Among the radio-loud population there is no evidence for any dependence of the merger fraction on either redshift or AGN power. For the matched radio-quiet samples, only 38%-15+16 are merging systems. The merger fraction for the sample of non-active galaxies at z\\gt 1 is indistinguishable from radio-quiet objects. This is strong evidence that mergers are the triggering mechanism for the radio-loud AGN phenomenon and the launching of relativistic jets from supermassive black holes (SMBHs). We speculate that major black hole (BH)–BH mergers play a major role in spinning up the central SMBHs in these objects.

  7. Recurrent Activity in Radio Galaxies

    SciTech Connect

    Jamrozy, Marek; Konar, Chiranjib; Machalski, Jerzy; Mack, Karl-Heinz; Saikia, Dhruba; Siemiginowska, Aneta; Stawarz, Lukasz; /KIPAC, Menlo Park /Jagiellonian U.

    2007-10-15

    One of the outstanding issues concerning extragalactic radio sources is the total duration of their active phase and the possible existence of duty cycles of their nuclear activity. A duty cycle can be recognized if there is a mechanism which preserves the information of past activity for a sufficiently long time after a new activity has started up. If a new cycle starts before the radio lobes created during a former activity period have faded, we can recognize this by the observations of a young radio source embedded in an old relic structure.

  8. Dying radio galaxies in clusters

    NASA Astrophysics Data System (ADS)

    Murgia, M.; Parma, P.; Mack, K.-H.; de Ruiter, H. R.; Fanti, R.; Govoni, F.; Tarchi, A.; Giacintucci, S.; Markevitch, M.

    2011-02-01

    Aims: We present a study of five "dying" nearby (z ≤ 0.2) radio galaxies belonging to both the WENSS minisurvey and the B2 bright catalogs WNB1734+6407, WNB1829+6911, WNB1851+5707, B2 0120+33, and B2 1610+29. Methods: These sources have been selected on the basis of their extremely steep broad-band radio spectra, which strongly indicates that either these objects belong to the rare class of dying radio galaxies or we are observing "fossil" radio plasma remaining from a previous instance of nuclear activity. We derive the relative duration of the dying phase from the fit of a synchrotron radiative model to the radio spectra of the sources. Results: The modeling of the integrated spectra and the deep spectral index images obtained with the VLA confirmed that in these sources the central engine has ceased to be active for a significant fraction of their lifetime, although their extended lobes have not yet completely faded away. We found that WNB1851+5707 is in reality composed of two distinct dying galaxies, which appear blended together as a single source in the WENSS. In the cases of WNB1829+6911 and B2 0120+33, the fossil radio lobes are seen in conjunction with a currently active core. A very faint core is also detected in a MERLIN image of WNB1851+5707a, one of the two dying sources composing WNB1851+5707. We found that all sources in our sample are located (at least in projection) at the center of an X-ray emitting cluster. Conclusions: Our results suggest that the duration of the dying phase for a radio source in a cluster can be significantly higher than that of a radio galaxy in the field, although no firm conclusions can be drawn because of the small number statistics involved. The simplest interpretation of the tendency for dying galaxies to be found in clusters is that the low-frequency radio emission from the fading radio lobes lasts longer if their expansion is somewhat reduced or even stopped. Another possibility is that the occurrence of dying

  9. The Helios radio astronomy experiment

    NASA Technical Reports Server (NTRS)

    Kayser, S.; Stone, R.

    1984-01-01

    Radio bursts traveling between the Sun and the Earth were tracked by radio astronomy experiments on Helios 1 and 2. A relatively short dipole antenna with a well-defined toroidal reception pattern was flown. The antenna spins in the ecliptic at 60.3 rpm and 2 frequencies are measured in each revolution. The signal analysis determines the strength of the signal, the direction of the source in the ecliptic, and the degree of modulation, and estimates source size. The experiments provide three-dimensional direction finding in space. They extend the radio frequency window beyond what is observable on Earth, and offer a long triangulation baseline.

  10. 46 CFR 15.830 - Radio officers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Radio officers. 15.830 Section 15.830 Shipping COAST... Computations § 15.830 Radio officers. Radio officers are required on certain merchant vessels of the United States. The determination of when a radio officer is required is based on the Federal...

  11. 46 CFR 15.830 - Radio officers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Radio officers. 15.830 Section 15.830 Shipping COAST... Computations § 15.830 Radio officers. Radio officers are required on certain merchant vessels of the United States. The determination of when a radio officer is required is based on the Federal...

  12. 46 CFR 15.830 - Radio officers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Radio officers. 15.830 Section 15.830 Shipping COAST... Computations § 15.830 Radio officers. Radio officers are required on certain merchant vessels of the United States. The determination of when a radio officer is required is based on the Federal...

  13. 46 CFR 15.830 - Radio officers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Radio officers. 15.830 Section 15.830 Shipping COAST... Computations § 15.830 Radio officers. Radio officers are required on certain merchant vessels of the United States. The determination of when a radio officer is required is based on the Federal...

  14. EVA Radio DRATS 2011 Report

    NASA Technical Reports Server (NTRS)

    Swank, Aaron J.; Bakula, Casey J.

    2012-01-01

    In the Fall of 2011, National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) participated in the Desert Research and Technology Studies (DRATS) field experiments held near Flagstaff, Arizona. The objective of the DRATS outing is to provide analog mission testing of candidate technologies for space exploration, especially those technologies applicable to human exploration of extra- terrestrial rocky bodies. These activities are performed at locations with similarities to extra-terrestrial conditions. This report describes the Extravehicular Activity (EVA) Dual-Band Radio Communication System which was demonstrated during the 2011 outing. The EVA radio system is designed to transport both voice and telemetry data through a mobile ad hoc wireless network and employs a dual-band radio configuration. Some key characteristics of this system include: 1. Dual-band radio configuration. 2. Intelligent switching between two different capability wireless networks. 3. Self-healing network. 4. Simultaneous data and voice communication.

  15. Ganymede: A New Radio Source

    NASA Technical Reports Server (NTRS)

    Kurth, W. S.; Gurnett, D. A.; Roux, A.; Bolton, S. J.

    1997-01-01

    Observations by the Galileo plasma wave receiver during the first two flybys of Ganymede revealed that this Jovian moon is the source of narrowband electromagnetic radio waves, making it the only satellite in the solar system known to generate non-thermal radio emissions. The emissions are the result of mode-coupling from electrostatic electron cyclotron emissions mu the upper hybrid resonance frequency, similar to non-thermal continuum radiation found at the known magnetized planets.

  16. Radio emission from supernova remnants

    NASA Astrophysics Data System (ADS)

    Dubner, Gloria; Giacani, Elsa

    2015-09-01

    The explosion of a supernova releases almost instantaneously about 10^{51} ergs of mechanic energy, changing irreversibly the physical and chemical properties of large regions in the galaxies. The stellar ejecta, the nebula resulting from the powerful shock waves, and sometimes a compact stellar remnant, constitute a supernova remnant (SNR). They can radiate their energy across the whole electromagnetic spectrum, but the great majority are radio sources. Almost 70 years after the first detection of radio emission coming from an SNR, great progress has been achieved in the comprehension of their physical characteristics and evolution. We review the present knowledge of different aspects of radio remnants, focusing on sources of the Milky Way and the Magellanic Clouds, where the SNRs can be spatially resolved. We present a brief overview of theoretical background, analyze morphology and polarization properties, and review and critically discuss different methods applied to determine the radio spectrum and distances. The consequences of the interaction between the SNR shocks and the surrounding medium are examined, including the question of whether SNRs can trigger the formation of new stars. Cases of multispectral comparison are presented. A section is devoted to reviewing recent results of radio SNRs in the Magellanic Clouds, with particular emphasis on the radio properties of SN 1987A, an ideal laboratory to investigate dynamical evolution of an SNR in near real time. The review concludes with a summary of issues on radio SNRs that deserve further study, and analysis of the prospects for future research with the latest-generation radio telescopes.

  17. Radio astronomy. [principles and observations

    NASA Technical Reports Server (NTRS)

    Alexander, J.; Clark, T.

    1974-01-01

    The origins, generation, detection, and interpretation of radio signals are discussed for signals with an assumed random polarization. After defining the basic parameters, the discussion moves to such topics as synchrotron radiation, plasma effects, changes in the electron energy spectrum in the radiating regions, energy loss to ionization, bremsstrahlung, radio astronomical observations of high-energy particles, emission by energetic particles, observation of supernova remnants and pulsars, galactic background continuum radiation, and others.

  18. Radio Telescope Gets Star Treatment

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2013-11-01

    Actress Jodie Foster, who played a scientist in search of extraterrestrial life in the 1997 film Contact, narrates a new promotional film to reintroduce the public to the National Radio Astronomy Observatory's (NRAO) renovated Karl G. Jansky Very Large Array (VLA) radio telescope in New Mexico. The 24-minute film, Beyond the Visible, which will air in the VLA Visitor Center, focuses on the operation of the telescope and scientific achievements associated with it.

  19. Populations of extragalactic radio sources

    NASA Astrophysics Data System (ADS)

    Wall, J. V.

    In the late 1950s and early 1960s, radio sky surveys were the center of an intense and public debate -- Big-Bang versus Steady-State cosmology -- the arguments revolving about source counts and statistical interpretations in the face of instrumental complications. The 1965 discovery of the microwave background took the fire from the debate, but left the momentum in place for large-area radio surveys at different frequencies, and for extensive identification/redshift-measurement programs. By the 1970s the data enabled us to start disentangling the different populations of extragalactic radio sources. We could refine our taxonomy, and we could view the possibility of delineating individual cosmic histories and evolutions. We could at least describe a goal to elucidate the birth-life-death cycles of the objects involved 1quasi-stellar objects (QSOs) and radio galaxies: together the 'active galactic nuclei' (AGNs)1 whose unaccountably prodigious energies somehow produce the beautifully aligned radio structures with which we are now familiar. One part of John Bolton's vision was to see how distorted a view of the AGN universe the original long-wavelength surveys provided. One legacy is thus the 'short-wavelength survey' for extragalactic radio sources, which has done so much to balance our picture of the radio sky. And indeed the legacy continues in the form of the immense sky surveys at present under way, complete with their sub-industries of radio-positioning and identification. From these, yet further results are emerging on spatial distribution and the skeleton structure of the universe. It is the purpose of this paper to outline something of this current view of the populations, their differences, similarities and unifying concepts.

  20. A zero-power radio receiver.

    SciTech Connect

    Brocato, Robert Wesley

    2004-09-01

    This report describes both a general methodology and some specific examples of passive radio receivers. A passive radio receiver uses no direct electrical power but makes sole use of the power available in the radio spectrum. These radio receivers are suitable as low data-rate receivers or passive alerting devices for standard, high power radio receivers. Some zero-power radio architectures exhibit significant improvements in range with the addition of very low power amplifiers or signal processing electronics. These ultra-low power radios are also discussed and compared to the purely zero-power approaches.

  1. Radio transients: an antediluvian review

    NASA Astrophysics Data System (ADS)

    Fender, R. P.; Bell, M. E.

    2011-09-01

    We are at the dawn of a new golden age for radio astronomy, with a new generation of facilities under construction and the global community focused on the Square Kilometre Array as its goal for the next decade. These new facilities offer orders of magnitude improvements in survey speed compared to existing radio telescopes and arrays. Furthermore, the study of transient and variable radio sources, and what they can tell us about the extremes of astrophysics as well as the state of the diffuse intervening media, have been embraced as key science projects for these new facilities. In this paper we review the studies of the populations of radio transients made to date, largely based upon archival surveys. Many of these radio transients and variables have been found in the image plane, and their astrophysical origin remains unclear. We take this population and combine it with sensitivity estimates for the next generation arrays to demonstrate that in the coming decade we may find ourselves detecting 10^5 image plane radio transients per year, providing a vast and rich field of research and an almost limitless set of targets for multi-wavelength follow up.

  2. Radio galaxies and their environment

    SciTech Connect

    van Breugel, W.

    1993-02-24

    The relationships between radio galaxies and their environment are varied, complex, and evolve with cosmic epoch. Basic questions are what role the environment plays in triggering and fuelling (radio) galaxy activity what the effects of this activity are on its environment, and how radio galaxies and environment evolve. Clearly, this could be the topic of a workshop all in itself and the scope of this review will necessarily be limited. A review of the connections between environment and galaxy activity in general has been given by Heckman. First, I will briefly summarize the relationships between parent galaxy and cluster environments, and radio galaxies. A more detailed discussion of various aspects of this will be given elsewhere by F. Owen, J.0. Burns and R. Perley. I will then discuss the current status of investigations of extended emission-line regions in radio galaxies, again referring elsewhere in this volume for more detailed discussions of some particular aspects (kinematics and ionization mechanisms by K. Meisenheimer; polarization and spectral index lobe asymmetries by G. Pooley). I will conclude with a brief discussion of the current status of observations of high redshift radio galaxies.

  3. Natural radio lasing at Jupiter

    NASA Technical Reports Server (NTRS)

    Calvert, W.; Leblanc, Y.; Ellis, G. R. A.

    1988-01-01

    Like the comparable AKR radio emissions from earth's magnetosphere, the well-known decametric radio S-bursts from Jupiter, observed in France and Australia at frequencies from 10 to 26 MHz, have been found to exhibit equally spaced discrete spectral components which can be attributed to the adjacent longitudinal oscillation modes of natural radio lasers. Implying sizes of only a few kilometers for the individual radio lasers producing the S-bursts, the frequency spacing of these modes was roughly constant with frequency and about 30 to 50 kHz. Their corresponding temporal spacings, however, varied inversely proportional to the observing frequency, suggesting that the radio lasers producing the S-bursts were expanding uniformly at a rate of about 4 km/s. Presumably caused by the projected motion of Io with respect to the planet, this expansion of the S-burst radio lasers would account for the downward frequency drifts of the S-bursts without the energetic electron bunches which have heretofore always been assumed necessary to account for such behavior.

  4. Mechanism for fast radio bursts

    NASA Astrophysics Data System (ADS)

    Romero, G. E.; del Valle, M. V.; Vieyro, F. L.

    2016-01-01

    Fast radio bursts are mysterious transient sources likely located at cosmological distances. The derived brightness temperatures exceed by many orders of magnitude the self-absorption limit of incoherent synchrotron radiation, implying the operation of a coherent emission process. We propose a radiation mechanism for fast radio bursts where the emission arises from collisionless bremsstrahlung in strong plasma turbulence excited by relativistic electron beams. We discuss possible astrophysical scenarios in which this process might operate. The emitting region is a turbulent plasma hit by a relativistic jet, where Langmuir plasma waves produce a concentration of intense electrostatic soliton-like regions (cavitons). The resulting radiation is coherent and, under some physical conditions, can be polarized and have a power-law distribution in energy. We obtain radio luminosities in agreement with the inferred values for fast radio bursts. The time scale of the radio flare in some cases can be extremely fast, of the order of 1 0-3 s . The mechanism we present here can explain the main features of fast radio bursts and is plausible in different astrophysical sources, such as gamma-ray bursts and some active galactic nuclei.

  5. Information Content in Radio Waves: Student Investigations in Radio Science

    NASA Astrophysics Data System (ADS)

    Jacobs, K.; Scaduto, T.

    2013-12-01

    We describe an inquiry-based instructional unit on information content in radio waves, created in the summer of 2013 as part of a MIT Haystack Observatory (Westford, MA) NSF Research Experiences for Teachers (RET) program. This topic is current and highly relevant, addressing science and technical aspects from radio astronomy, geodesy, and atmospheric research areas as well as Next Generation Science Standards (NGSS). Projects and activities range from simple classroom demonstrations and group investigations, to long term research projects incorporating data acquisition from both student-built instrumentation as well as online databases. Each of the core lessons is applied to one of the primary research centers at Haystack through an inquiry project that builds on previously developed units through the MIT Haystack RET program. In radio astronomy, students investigate the application of a simple and inexpensive software defined radio chip (RTL-SDR) for use in systems implementing a small and very small radio telescope (SRT and VSRT). Both of these systems allow students to explore fundamental principles of radio waves and interferometry as applied to radio astronomy. In ionospheric research, students track solar storms from the initial coronal mass ejection (using Solar Dynamics Observatory images) to the resulting variability in total electron density concentrations using data from the community standard Madrigal distributed database system maintained by MIT Haystack. Finally, students get to explore very long-baseline interferometry as it is used in geodetic studies by measuring crustal plate displacements over time. Alignment to NextGen standards is provided for each lesson and activity with emphasis on HS-PS4 'Waves and Their Applications in Technologies for Information Transfer'.

  6. The radio properties of infrared-faint radio sources

    NASA Astrophysics Data System (ADS)

    Middelberg, E.; Norris, R. P.; Hales, C. A.; Seymour, N.; Johnston-Hollitt, M.; Huynh, M. T.; Lenc, E.; Mao, M. Y.

    2011-02-01

    Context. Infrared-faint radio sources (IFRS) are objects that have flux densities of several mJy at 1.4 GHz, but that are invisible at 3.6 μm when using sensitive Spitzer observations with μJy sensitivities. Their nature is unclear and difficult to investigate since they are only visible in the radio. Aims: High-resolution radio images and comprehensive spectral coverage can yield constraints on the emission mechanisms of IFRS and can give hints to similarities with known objects. Methods: We imaged a sample of 17 IFRS at 4.8 GHz and 8.6 GHz with the Australia Telescope Compact Array to determine the structures on arcsecond scales. We added radio data from other observing projects and from the literature to obtain broad-band radio spectra. Results: We find that the sources in our sample are either resolved out at the higher frequencies or are compact at resolutions of a few arcsec, which implies that they are smaller than a typical galaxy. The spectra of IFRS are remarkably steep, with a median spectral index of -1.4 and a prominent lack of spectral indices larger than -0.7. We also find that, given the IR non-detections, the ratio of 1.4 GHz flux density to 3.6 μm flux density is very high, and this puts them into the same regime as high-redshift radio galaxies. Conclusions: The evidence that IFRS are predominantly high-redshift sources driven by active galactic nuclei (AGN) is strong, even though not all IFRS may be caused by the same phenomenon. Compared to the rare and painstakingly collected high-redshift radio galaxies, IFRS appear to be much more abundant, but less luminous, AGN-driven galaxies at similar cosmological distances.

  7. Radio Stars or Radio Nebulae? - The Uncertainties of 1953

    NASA Astrophysics Data System (ADS)

    Sullivan, W. T., III

    1997-12-01

    By the early 1950s radio astronomers in England and Australia had assembled a handful of catalogues giving flux densities (at 100 MHz) and positions for a total of about 200 radio sources. But only a half dozen of these sources had suggested optical identifications and there raged a debate as to whether the radio sources as a whole were galactic or extragalactic. Furthermore, what was the relationship between these discrete radio sources and the strong galactic background radiation? Could a consistent model be constructed in which the background was the integrated radiation from the weaker members of the detected population? This paper aims to convey the uncertainty of astronomers in 1953. The primary data emanated from the surveys of Ryle, Smith and Elsmore (1950), Bolton, Stanley and Slee (1950), Mills (1952), and Hanbury Brown and Hazard (1953). Quoted position uncertainties were typically 0.5 to 2 degrees; even more discouraging, in overlapping regions the surveys seldom agreed. Optical identifications were rare and of varying degrees of acceptance, and in any case were about evenly split between galaxies (e.g., M31, Cyg A, Vir A) and galactic objects (e.g., Tau A = the Crab nebula, Cas A). And why were so many bright galaxies and gaseous nebulae not detected in the radio? Were there two classes of source, as suggested by Bernard Mills? If the bulk of the sources were extragalactic, what was their source of prodigious radio luminosity and why was it so much larger than the Milky Way's? If the background consisted of radio stars with a Population II distribution, was there also an isotropic extragalactic background component, as modelled by Jan Oort and Gart Westerhout (1950)? What in fact was the radiation mechanism for the sources and the background - free-free (but of what optical thickness?), synchrotron (but did the cosmic ray electrons exist?), or something else?

  8. IA-Regional-Radio - Social Network for Radio Recommendation

    NASA Astrophysics Data System (ADS)

    Dziczkowski, Grzegorz; Bougueroua, Lamine; Wegrzyn-Wolska, Katarzyna

    This chapter describes the functions of a system proposed for the music hit recommendation from social network data base. This system carries out the automatic collection, evaluation and rating of music reviewers and the possibility for listeners to rate musical hits and recommendations deduced from auditor's profiles in the form of regional Internet radio. First, the system searches and retrieves probable music reviews from the Internet. Subsequently, the system carries out an evaluation and rating of those reviews. From this list of music hits, the system directly allows notation from our application. Finally, the system automatically creates the record list diffused each day depending on the region, the year season, the day hours and the age of listeners. Our system uses linguistics and statistic methods for classifying music opinions and data mining techniques for recommendation part needed for recorded list creation. The principal task is the creation of popular intelligent radio adaptive on auditor's age and region - IA-Regional-Radio.

  9. RADIO VARIABILITY IN SEYFERT NUCLEI

    SciTech Connect

    Mundell, C. G.; Ferruit, P.; Nagar, N.; Wilson, A. S.

    2009-09-20

    Comparison of 8.4 GHz radio images of a sample of eleven, early-type Seyfert galaxies with previous observations reveals possible variation in the nuclear radio flux density in five of them over a seven year period. Four Seyferts (NGC 2110, NGC 3081, MCG -6-30-15, and NGC 5273) show a decline in their 8.4 GHz nuclear flux density between 1992 and 1999, while one (NGC 4117) shows an increase; the flux densities of the remaining six Seyferts (Mrk 607, NGC 1386, Mrk 620, NGC 3516, NGC 4968, and NGC 7465) have remained constant over this period. New images of MCG -5-23-16 are also presented. We find no correlation between radio variability and nuclear radio luminosity or Seyfert nuclear type, although the sample is small and dominated by type 2 Seyferts. Instead, a possible correlation between the presence of nuclear radio variability and the absence of hundred parsec-scale radio emission is seen, with four out of five marginally resolved or unresolved nuclei showing a change in nuclear flux density, while five out of six extended sources show no nuclear variability despite having unresolved nuclear sources. NGC 2110 is the only source in our sample with significant extended radio structure and strong nuclear variability ({approx}38% decline in nuclear flux density over seven years). The observed nuclear flux variability indicates significant changes are likely to have occurred in the structure of the nucleus on scales smaller than the VLA beam size (i.e., within the central {approx}0.''1 (15 pc)), between the two epochs, possibly due to the appearance and fading of new components or shocks in the jet, consistent with previous detection of subparsec-scale nuclear structure in this Seyfert. Our results suggest that all Seyferts may exhibit variation in their nuclear radio flux density at 8.4 GHz, but that variability is more easily recognized in compact sources in which emission from the variable nucleus is not diluted by unresolved, constant flux density radio jet

  10. Radio continuum polarimetric imaging of high redshift radio galaxies

    NASA Technical Reports Server (NTRS)

    Carilli, C. L.; Owen, F. N.; Harris, D. E.

    1994-01-01

    Multifrequency images of total and polarized radio continuum emission from the two high redshift radio galaxies 0902+343 (z = 3.40) and 0647+415 (4C 41.17, z = 3.80) are presented. These images represent the most sensitive polarimetric study of high redshift ratio galaxies to date. The emission from both galaxies is substantially polarized, up to 30% in some regions, and both sources sit behind deep 'Faraday screens,' producing large rotation measures, over 10(exp 3) rad/sq. m in magnitude, and large rotation measure gradients across the sources. Such large rotation measures provide further evidence that high redshift radio galaxies are situated in very dense environments. Drawing the analogy to a class of low redshift powerful radio galaxies with similarly large rotation measures, we suggest that 0902+343 and 0647+415 are situated at the centers of dense, x-ray 'colling flow' clusters, and that the cluster gas is substantially magnetized. The remarkable similarity between the optical and radio morphologies of 0647+415 on scales as small as 0.1 sec is presented. We consider, and reject, both synchrotron and inverse Compton radiation as possible sources of the optical emission. We also consider both scattering of light out of a 'cone' of radiation from an obscured nucleus, and jet-induced star formation, and find that both models encounter difficulties in explaining this remarkably close radio-optical alignment. High resolution spectral index images reveal compact, flat spectrum components in both sources. We suggest that these components are the active nuclei of the galaxies. Lastly, high resolution images of 0902+343 show that the southernmost component forms a 'ring' of 0.2 sec radius. We discuss the possibility that this ring is the result of gravitational lensing, along the lines proposed by Kochanek & Lawrence (1990).

  11. Industrial interference and radio astronomy

    NASA Astrophysics Data System (ADS)

    Jessner, A.

    2013-07-01

    The interferer - victim scenario is described for the case of industrial interference affecting radio astronomical observatories. The sensitivity of radio astronomical receivers and their interference limits are outlined. EMC above 30 MHz is a serious problem for Radio Astronomy. Interferer (CISPR) and victim (ITU-R RA 769) standards are not harmonised. The emissions from the interferer and their spectral characteristics are not defined sufficiently well by CISPR standards. The required minimum coupling losses (MCL) between an industrial device and radio astronomical antenna depends on device properties but is shown to exceed 140 dB in most cases. Spatial separation of a few km is insufficient on its own, the terrain must shield > 30-40 dB, additional mitigations such as extra shielding or suppression of high frequency emissions may be necessary. A case by case compatibility analysis and tailored EMC measures are required for individual installations. Aggregation of many weak rfi emitters can become serious problem. If deployment densities are high enough, the emission constraints can even exceed those for a single interferer at a short distance from the radio observatory. Compatibility studies must account not only for the single interferer but also for many widely distributed interference sources.

  12. Radio-Optical Imaging of ATLBS Survey

    NASA Astrophysics Data System (ADS)

    Thorat, Kshitij

    2011-12-01

    We present the radio-optical imaging of ATLBS, a sensitive radio survey (Subrahmanyan et al. 2010). The primary aim of the ATLBS survey is to image low-power radio sources which form the bulk of the radio source population to moderately high red-shifts ( z ˜ 1.0). The accompanying multiband optical and near infra-red observations provide information about the hosts and environments of the radio sources. We give here details of the imaging of the radio data and optical data for the ATLBS survey.

  13. Phenomenology of magnetospheric radio emissions

    NASA Technical Reports Server (NTRS)

    Carr, T. D.; Desch, M. D.; Alexander, J. K.

    1983-01-01

    Jupiter has now been observed over 24 octaves of the radio spectrum, from about 0.01 MHz to 300,000 MHz. Its radio emissions fill the entire spectral region where interplanetary electromagnetic propagation is possible at wavelengths longer than infrared. Three distinct types of radiation are responsible for this radio spectrum. Thermal emission from the atmosphere accounts for virtually all the radiation at the high frequency end. Synchrotron emission from the trapped high-energy particle belt deep within the inner magnetosphere is the dominant spectral component from about 4000 to 40 MHz. The third class of radiation consists of several distinct components of sporadic low frequency emission below 40 MHz. The decimeter wavelength emission is considered, taking into account the discovery of synchrotron emission, radiation by high-energy electrons in a magnetic field, and the present status of Jovian synchrotron phenomenology. Attention is also given to the decameter and hectometer wavelength emission, and emissions at kilometric wavelengths.

  14. Photoelectric spectrophotometry of radio galaxies

    NASA Technical Reports Server (NTRS)

    Yee, H. K. C.; Oke, J. B.

    1978-01-01

    The absolute energy distributions from 3200 to 10,000 A of 26 3CR radio galaxies are determined on the basis of spectrophotometric observations with the multichannel spectrometer of the Hale 5-m telescope. It is found that there is a continuous range of emission-line characteristics and UV excess in the sample and that a strong correlation exists between the nonthermal component luminosity and hydrogen emission, which favors the hypothesis that direct photoionization by the nuclear radiation is responsible for the emission lines observed. Calculations are performed which show that in almost all cases the power-law component model provides sufficient UV photons to produce the observed H-beta line. Indications are obtained that the optical nuclear component is related to the radio emission in some complex manner and that strong radio galaxies tend to be accompanied by UV excess and emission lines.

  15. Miniature EVA Software Defined Radio

    NASA Technical Reports Server (NTRS)

    Pozhidaev, Aleksey

    2012-01-01

    As NASA embarks upon developing the Next-Generation Extra Vehicular Activity (EVA) Radio for deep space exploration, the demands on EVA battery life will substantially increase. The number of modes and frequency bands required will continue to grow in order to enable efficient and complex multi-mode operations including communications, navigation, and tracking applications. Whether conducting astronaut excursions, communicating to soldiers, or first responders responding to emergency hazards, NASA has developed an innovative, affordable, miniaturized, power-efficient software defined radio that offers unprecedented power-efficient flexibility. This lightweight, programmable, S-band, multi-service, frequency- agile EVA software defined radio (SDR) supports data, telemetry, voice, and both standard and high-definition video. Features include a modular design, an easily scalable architecture, and the EVA SDR allows for both stationary and mobile battery powered handheld operations. Currently, the radio is equipped with an S-band RF section. However, its scalable architecture can accommodate multiple RF sections simultaneously to cover multiple frequency bands. The EVA SDR also supports multiple network protocols. It currently implements a Hybrid Mesh Network based on the 802.11s open standard protocol. The radio targets RF channel data rates up to 20 Mbps and can be equipped with a real-time operating system (RTOS) that can be switched off for power-aware applications. The EVA SDR's modular design permits implementation of the same hardware at all Network Nodes concept. This approach assures the portability of the same software into any radio in the system. It also brings several benefits to the entire system including reducing system maintenance, system complexity, and development cost.

  16. Radio Relays Improve Wireless Products

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Signal Hill, California-based XCOM Wireless Inc. developed radio frequency micromachine (RF MEMS) relays with a Phase II Small Business Innovation Research (SBIR) contract through NASA?s Jet Propulsion Laboratory. In order to improve satellite communication systems, XCOM produced wireless RF MEMS relays and tunable capacitors that use metal-to-metal contact and have the potential to outperform most semiconductor technologies while using less power. These relays are used in high-frequency test equipment and instrumentation, where increased speed can mean significant cost savings. Applications now also include mainstream wireless applications and greatly improved tactical radios.

  17. Blazars at Low Radio Frequencies

    NASA Astrophysics Data System (ADS)

    Trüstedt, J.; Kadler, M.; Brüggen, M.; Falcke, H.; Heald, G.; McKean, J.; Mueller, C.; Ros, E.; Schulz, R.; Wilms, J.

    We explore the low radio-frequency properties of the MOJAVE 1 blazar sample using the LOFAR Multi-Frequency Snapshot Sky Survey (MSSS). We find the characteristically flat blazar spectrum to extend down to the LOFAR bands, demonstrating that the emission at these low radio frequencies is still dominated by relativistically beamed emission. As most sources remain unresolved at the MSSS angular resolution, we are reimaging these data using LOFAR baselines beyond the standard MSSS uv-range resulting in an angular resolution of ~24 arcsec. We present first LOFAR images of MOJAVE sources from this project.

  18. Mobile radio interferometric geodetic systems

    NASA Technical Reports Server (NTRS)

    Macdoran, P. F.; Niell, A. E.; Ong, K. M.; Resch, G. M.; Morabito, D. D.; Claflin, E. S.; Lockhart, T. G.

    1978-01-01

    Operation of the Astronomical Radio Interferometric Earth Surveying (ARIES) in a proof of concept mode is discussed. Accuracy demonstrations over a short baseline, a 180 km baseline, and a 380 km baseline are documented. Use of ARIES in the Sea Slope Experiment of the National Geodetic Survey to study the apparent differences between oceanographic and geodetic leveling determinations of the sea surface along the Pacific Coast is described. Intergration of the NAVSTAR Global Positioning System and a concept called SERIES (Satellite Emission Radio Interferometric Earth Surveying) is briefly reviewed.

  19. Radio Galaxies in Abell Rich Clusters

    NASA Astrophysics Data System (ADS)

    Ledlow, M. J.

    1994-05-01

    We have defined a complete sample of radio galaxies chosen from Abell's northern catalog consisting of all clusters with measured redshifts < 0.09. This sample consists of nearly 300 clusters. A multiwavelength survey including optical CCD R-Band imaging, optical spectroscopy, and VLA 20 cm radio maps has been compiled. I have used this database to study the optical/radio properties of radio galaxies in the cluster environment. In particular, optical properties have been compared to a radio-quiet selected sample to look for optical signatures which may distinguish radio galaxies from normal radio-quiet ellipticals. The correlations between radio morphology and galaxy type, the optical dependence of the FR I/II break, and the univariate and bivariate luminosity functions have been examined for this sample. This study is aimed at understanding radio galaxies as a population and examining their status in the AGN heirarchy. The results of this work will be applied to models of radio source evolution. The results from the optical data analysis suggest that radio galaxies, as a class, cannot be distinguished from non-radio selected elliptical galaxies. The magnitude/size relationship, the surface-brightness profiles, the fundamental plane, and the intrinsic shape of the radio galaxies are consistent between our radio galaxy and control sample. The radio galaxies also trace the elliptical galaxy optical luminosity function in clusters very well; with many more L(*) galaxies than brightest cluster members. Combined with the results of the spectroscopy, the data are consistent with the idea that all elliptical galaxies may at some point in their lifetimes become radio sources. In conclusion, I present a new observational picture for radio galaxies and discuss the important properties which may determine the evolution of individual sources.

  20. Cosmology: Home of a fast radio burst

    NASA Astrophysics Data System (ADS)

    Lorimer, Duncan

    2016-02-01

    Our understanding of fast radio bursts -- intense pulses of radio waves -- and their use as cosmic probes promises to be transformed now that one burst has been associated with a galaxy of known distance from Earth. See Letter p.453

  1. Radio frequency power load and associated method

    NASA Technical Reports Server (NTRS)

    Sims, III, William Herbert (Inventor); Chavers, Donald Gregory (Inventor); Richeson, James J. (Inventor)

    2010-01-01

    A radio frequency power load and associated method. A radio frequency power load apparatus includes a container and a fluid having an ion source therein, the fluid being contained in the container. Two conductors are immersed in the fluid. A radio frequency transmission system includes a radio frequency transmitter, a radio frequency amplifier connected to the transmitter and a radio frequency power load apparatus connected to the amplifier. The apparatus includes a fluid having an ion source therein, and two conductors immersed in the fluid. A method of dissipating power generated by a radio frequency transmission system includes the steps of: immersing two conductors of a radio frequency power load apparatus in a fluid having an ion source therein; and connecting the apparatus to an amplifier of the transmission system.

  2. Observational aspects of stellar radio flares

    NASA Technical Reports Server (NTRS)

    Bookbinder, Jay A.

    1991-01-01

    The study of stellar flares in the radio regime provides a nearly unique observational perspective, as the emission generally arises from the particle acceleration region. Continuum and spectral studies of radio burst emission for several classes of stars are reviewed, and some preliminary connections with the quiescent radio emission from flare stars are made. Further, the radio observations are placed in a broader observational context provided by X-ray, UV, and optical observations.

  3. New vistas in planetary radio astronomy

    NASA Technical Reports Server (NTRS)

    Alexander, J. K., Jr.

    1976-01-01

    Recent progress in planetary radio astronomy is reviewed, where the most significant advances have come from spacecraft observations. The low-frequency radio spectra of the earth, Jupiter, and Saturn are compared, and the striking similarity in shapes is noted. New radio data are examined which provide a way to compare the magnetic field strengths of the planets. More detailed information on the radio structures of Jupiter and Saturn, and possibly on Uranus, is expected from the 1977 Mariner Jupiter-Saturn mission.

  4. RadioActive101 Practices

    ERIC Educational Resources Information Center

    Brites, Maria José; Ravenscroft, Andrew; Dellow, James; Rainey, Colin; Jorge, Ana; Santos, Sílvio Correia; Rees, Angela; Auwärter, Andreas; Catalão, Daniel; Balica, Magda; Camilleri, Anthony F.

    2014-01-01

    In keeping with the overarching RadioActive101 (RA101) spirit and ethos, this report is the product of collaborative and joined-up thinking from within the European consortium spread across five countries. As such, it is not simply a single voice reporting on the experiences and knowledge gained during the project. Rather it is a range of…

  5. The Sources of Radio News.

    ERIC Educational Resources Information Center

    Whitney, D. Charles

    To examine the production of programing material in a radio newsroom, a study was undertaken of the sources presented to the newsroom, of sources within the sources, of sources actively sought by the news staff, of degrees of processing of news items, and of the sources comprising the news output. Information in each of these areas was collected…

  6. Meteors by radio: Getting started

    NASA Astrophysics Data System (ADS)

    Lonc, William

    1999-02-01

    A system for detecting meteors by radio is described which is simple and reliable, and thought to be suitable as a science fair project. There is a relatively detailed discussion of the various factors involved in such a project, along with some typical results to indicate the kind of data that is possible.

  7. Radio's role in popular education.

    PubMed

    Valderrama, M

    1988-01-01

    Many theorists in the 1950's and 1960's thought that mass communications media would be a major factor in integrating and modernizing developing countries. International organizations and Western governments supported educational programs on sanitation and agriculture technology for developing countries. However, Western technology did not suit the rural areas of the developing world. The programs often did not reach the people who needed them the most, but only the educated few. The Catholic church has developed a radio network in Colombia that combines commercial and cultural or religious programs. In addition, 42 church organizations are producing radio programs in Latin America. Most of these programs have not been successful in formal education in history, health care, and agriculture technology. This indicates that radio may not be a good medium for scientific information; audiences don't listen often enough and concentrate adequately to gain from this kind of teaching. It can, however, be effective in spreading cultural information and voicing opinions and views. Educational radio programming is useful when the subject matter is closely linked to specific problems in the community. It must be expressed in the terms of the local audience, as in the rural areas of Latin America. Presentations should not be in the teacher format but in forums, dramas, and documentary reports, and delivered in the local language. PMID:12282828

  8. Bolivia: instruction through interactive radio.

    PubMed

    Teas, M M; Tilson, T

    1989-01-01

    The Education Development Center in Bolivia is developing and testing a new application for interactive radio instruction (IRI) to teach health in primary schools. The project is funded by USAID and has been undertaken to help the Bolivian government include health education in primary schools as part of a strategy to reduce child mortality. Each radio health program will be broadcast weekly for school children in twenty-minute segments. The broadcasts and complementary post-broadcast activities will give special emphasis to child survival topics such as oral rehydration therapy and nutrition. Special features include IRI scripts which simulate interaction between the radio teacher and the students, new topics introduced in a systematic way engaging students in problem-solving activities, and extensive oral and written student participation. Complementary IRI program materials will include take-home exercises designed to involve family participation, and teachers' guides to provide teachers with practical hands-on activities to strengthen children's understanding of basic health concepts. Short, in-service training sessions will prepare teachers to facilitate radio classes and carry out post-broadcast activities with students. The potential of IRI to improve student and teacher understanding of health and nutrition is only beginning to be recognized. PMID:12346418

  9. Workplace Training at SBS Radio.

    ERIC Educational Resources Information Center

    Simons, Lynette

    2001-01-01

    Notes that at Australia's Special Broadcasting Services Radio, workplace training is an essential requirement for on-air staff but a degree in journalism or communications is an enormous advantage. Describes several in-house accredited competency-based modules in journalism and broadcasting. (RS)

  10. International Radio Broadcasting: Who Listens?

    ERIC Educational Resources Information Center

    Browne, Donald R.

    It is difficult to obtain reliable data on the nature of the audience for international broadcast programs in Asia (e.g., those beamed by the Voice of America or Radio Japan). However, analysis of listener mail and some survey research have provided a fairly clear profile of the audience: young (ages 15-34), well educated, urban, male (but with a…

  11. Digital Audio Radio Field Tests

    NASA Technical Reports Server (NTRS)

    Hollansworth, James E.

    1997-01-01

    Radio history continues to be made at the NASA Lewis Research Center with the beginning of phase two of Digital Audio Radio testing conducted by the Consumer Electronic Manufacturers Association (a sector of the Electronic Industries Association and the National Radio Systems Committee) and cosponsored by the Electronic Industries Association and the National Association of Broadcasters. The bulk of the field testing of the four systems should be complete by the end of October 1996, with results available soon thereafter. Lewis hosted phase one of the testing process, which included laboratory testing of seven proposed digital audio radio systems and modes (see the following table). Two of the proposed systems operate in two modes, thus making a total of nine systems for testing. These nine systems are divided into the following types of transmission: in-band on channel (IBOC), in-band adjacent channel (IBAC), and new bands - the L-band (1452 to 1492 MHz) and the S-band (2310 to 2360 MHz).

  12. Hybrid spread spectrum radio system

    DOEpatents

    Smith, Stephen F [London, TN; Dress, William B [Camas, WA

    2010-02-09

    Systems and methods are described for hybrid spread spectrum radio systems. A method, includes receiving a hybrid spread spectrum signal including: fast frequency hopping demodulating and direct sequence demodulating a direct sequence spread spectrum signal, wherein multiple frequency hops occur within a single data-bit time and each bit is represented by chip transmissions at multiple frequencies.

  13. A repeating fast radio burst

    NASA Astrophysics Data System (ADS)

    Spitler, L. G.; Scholz, P.; Hessels, J. W. T.; Bogdanov, S.; Brazier, A.; Camilo, F.; Chatterjee, S.; Cordes, J. M.; Crawford, F.; Deneva, J.; Ferdman, R. D.; Freire, P. C. C.; Kaspi, V. M.; Lazarus, P.; Lynch, R.; Madsen, E. C.; McLaughlin, M. A.; Patel, C.; Ransom, S. M.; Seymour, A.; Stairs, I. H.; Stappers, B. W.; van Leeuwen, J.; Zhu, W. W.

    2016-03-01

    Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star.

  14. PRELIMINARY RESULTS OF RADIO PASTEURIZATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Radio frequency energy was investigated as a nonthermal alternative to thermal pasteurization. Two RF power supply systems were assembled and provided frequencies in the range of 20 kHz to 27 MHz. Electric field strengths of 14 to 30 kV/cm were applied to suspensions of Saccharomyces cerevisiae i...

  15. Dictionary of Radio and Television.

    ERIC Educational Resources Information Center

    Pannett, W. E.

    This dictionary presents definitions of both the well-established terms and many new ones that have come into use with the advances that have taken place in the fields of radio and television. In many cases extended definitions are given in order to describe briefly elementary principles and circuits, while newer and more complex devices and…

  16. Counselor Effectiveness Through Radio Communication.

    ERIC Educational Resources Information Center

    Tentoni, Stuart C.

    This study determined the effectiveness of the use of radio as a means of providing immediate feedback on student counselors in a practicum setting. Using a non-equivalent group experimental design, 10 experimental subjects were compared to 10 control subjects with respect to counselor effectiveness. The experimental subjects were given immediate…

  17. Radio Days in the Classroom

    ERIC Educational Resources Information Center

    Schuchat, Dan

    2005-01-01

    What social studies project challenges students with interdisciplinary learning, engages their various abilities and learning styles, offers them the opportunity for collaborative work-and encourages them to speak in strange voices? The answer is an eighth grade radio drama project. For most of the month of March 2004, the entire eighth grade at…

  18. A repeating fast radio burst.

    PubMed

    Spitler, L G; Scholz, P; Hessels, J W T; Bogdanov, S; Brazier, A; Camilo, F; Chatterjee, S; Cordes, J M; Crawford, F; Deneva, J; Ferdman, R D; Freire, P C C; Kaspi, V M; Lazarus, P; Lynch, R; Madsen, E C; McLaughlin, M A; Patel, C; Ransom, S M; Seymour, A; Stairs, I H; Stappers, B W; van Leeuwen, J; Zhu, W W

    2016-03-10

    Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star. PMID:26934226

  19. Epsiodic Activity in Radio Galaxies

    SciTech Connect

    Saikia, D.J.; Konar, C.; Jamrozy, M.; Machalski, J.; Gupta, Neeraj; Stawarz, L.; Mack, K.-H.; Siemiginowska, A.; /Harvard-Smithsonian Ctr. Astrophys.

    2007-10-15

    One of the interesting issues in our understanding of active galactic nuclei is the duration of their active phase and whether such activity is episodic. In this paper we summarize our recent results on episodic activity in radio galaxies obtained with the GMRT and the VLA.

  20. Kashima 34-m Radio Telescope

    NASA Technical Reports Server (NTRS)

    Sekido, Mamoru; Kawai, Eiji

    2013-01-01

    The Kashima 34-m radio telescope has been continuously operated and maintained by the National Institute of Information and Communications Technology (NICT) as a facility of the Kashima Space Technology Center (KSTC) in Japan. This brief report summarizes the status of this telescope, the staff, and activities during 2012.

  1. Low Frequency Radio Experiment (LORE)

    NASA Astrophysics Data System (ADS)

    Manoharan, P. K.; Naidu, Arun; Joshi, B. C.; Roy, Jayashree; Kate, G.; Pethe, Kaiwalya; Galande, Shridhar; Jamadar, Sachin; Mahajan, S. P.; Patil, R. A.

    2016-03-01

    In this paper, we present a case study of Low Frequency Radio Experiment (LORE) payload to probe the corona and the solar disturbances at solar offsets greater than 2 solar radii, i.e., at frequencies below 30 MHz. The LORE can be complimentary to the planned Indian solar mission, “Aditya-L1” and its other payloads as well as synergistic to ground-based interplanetary scintillation (IPS) observations, which are routinely carried out by the Ooty Radio Telescope. We discuss the baseline design and technical details of the proposed LORE and its particular suitability for providing measurements on the detailed time and frequency structure of fast drifting type-III and slow drifting type-II radio bursts with unprecedented time and frequency resolutions. We also brief the gonio-polarimetry, which is possible with better-designed antennas and state-of-the-art electronics, employing FPGAs and an intelligent data management system. These would enable us to make a wide range of studies, such as nonlinear plasma processes in the Sun-Earth distance, in-situ radio emission from coronal mass ejections (CMEs), interplanetary CME driven shocks, nature of ICMEs driving decelerating IP shocks and space weather effects of solar wind interaction regions.

  2. The Auger Engineering Radio Array

    NASA Astrophysics Data System (ADS)

    Fuchs, Benjamin

    2012-11-01

    High and ultra-high energy cosmic rays hitting the Earth's atmosphere cause extensive air showers (EAS). In recent years, these cosmic rays have been extensively studied at the Pierre Auger Observatory in Argentina. The EAS mainly consist of charged particles, especially electrons and positrons, which cause electro-magnetic emission in the MHz range by interaction with the Earth's magnetic field. To measure this radio emission, AERA, the Auger Engineering Radio Array, was deployed in October 2010 and commenced regular data acquisition in April 2011. AERA was designed as an engineering array for technology and methodology development towards future large-scale radio arrays. It will allow studies on the radio emission mechanism and the physics capabilities of the detection technique. AERA's unique site within the surface detector array (SD) of the Pierre Auger Observatory provides the possibility of coincident hybrid and super-hybrid EAS detection especially in overlap with the fluorescence telescopes Coihueco and HEAT. Besides a description of the setup, we present an overview of analyses of commissioning data taken between November 2010 and April 2011. Also, we show the first hybrid and self-triggered events detected with AERA in April 2011.

  3. 47 CFR 90.185 - Multiple licensing of radio transmitting equipment in the mobile radio service.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Multiple licensing of radio transmitting equipment in the mobile radio service. 90.185 Section 90.185 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES...

  4. 47 CFR 90.185 - Multiple licensing of radio transmitting equipment in the mobile radio service.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Multiple licensing of radio transmitting equipment in the mobile radio service. 90.185 Section 90.185 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES...

  5. 47 CFR 90.185 - Multiple licensing of radio transmitting equipment in the mobile radio service.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Multiple licensing of radio transmitting equipment in the mobile radio service. 90.185 Section 90.185 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES...

  6. 47 CFR 90.185 - Multiple licensing of radio transmitting equipment in the mobile radio service.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Multiple licensing of radio transmitting equipment in the mobile radio service. 90.185 Section 90.185 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES...

  7. 47 CFR 90.185 - Multiple licensing of radio transmitting equipment in the mobile radio service.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Multiple licensing of radio transmitting equipment in the mobile radio service. 90.185 Section 90.185 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES...

  8. Sprite Luminosity and Radio Noise

    NASA Astrophysics Data System (ADS)

    Fullekrug, M.; Evans, A.; Mezentsev, A.; van der Velde, O.; Soula, S.

    2013-12-01

    Sprites are composed of individual streamer discharges (e.g., Pasko, 2010) which split into streamer tips (McHarg et al., 2010) with diameters 50-100 m at 60-80 km height (Kanmae et al., 2012). The sprite luminosity coincides in time and space with extremely low frequency electromagnetic radiation <3 kHz in excellent agreement with theory (Cummer and Fullekrug, 2001). This theory is based on current flowing in the body of sprites at 70-80 km height associated with large streamer densities (Pasko et al., 1998). A more detailed study shows specifically that the exponential growth and splitting of streamers at 70-80 km height results in an electron multiplication associated with the acceleration of electrons to a few eV. The accelerated electrons radiate a small amount of electromagnetic energy and the incoherent superposition of many streamers causes the observed electromagnetic radiation (Qin et al., 2012). It has been predicted that this newly recognized physical mechanism might also result in low frequency ( 30-300 kHz) electromagnetic radiation emanating from sprite streamers near 40 km height in the stratosphere, albeit with very small magnetic fields 10^{-17}-10^{-12} T from a single streamer (Qin et al., 2012). The presence of this predicted radiation was promptly confirmed by low frequency radio noise measurements during dancing sprites with a very sensitive radio receiver (Fullekrug et al., 2013). Specifically, it was found that the sprite luminosity coincides with sudden enhancements of the radio noise. These initial observations are extended here with a more detailed analysis to study the spatial coherence of the radio noise recorded with a novel network of sensitive radio receivers deployed during field work in the summer 2013. This network of radio receivers is used to study the relationship between the radio noise and the sprite luminosity observed with video cameras. The sprite luminosity is inferred from video recordings by use of sophisticated image

  9. Politics and Radio in the 1924 Campaign.

    ERIC Educational Resources Information Center

    Berkman, Dave

    1987-01-01

    Discusses the relation between radio broadcasting and politics in the 1924 presidential campaign, focusing on newspaper and magazine coverage. Notes radio's influence on candidate image, the aspect of censorship, and the use of radio during the campaign and after the election. (MM)

  10. Metsaehovi Radio Observatory Annual Report 1998

    NASA Astrophysics Data System (ADS)

    Urpo, S.; Mujunen, A.

    1999-01-01

    Contents include the following: Introduction; Research Activities; Radio Astronomical Instrumentation; Extragalactic Radio Sources; Observations with Other Facilities; VLBI Research; Solar Research; HRDL for Alpha Magnetic Spectrometer (AMS); Radio Spectroscopy; Publications; Visits to Foreign Institutes; Visiting Scientists; Teaching; Other Activities; Personnel in 1998; and List of Figures.

  11. International Radio Regulations Resulting from WARC 1979.

    ERIC Educational Resources Information Center

    Berrada, Abderrazak

    The main features of international regulations on radio communications of the International Telecommunication Union are summarized and the possible effects on these regulations of the World Administrative Radio Conference of 1979 (WARC-79) are discussed in this paper. It is noted that while the international radio regulations are regarded as…

  12. Packet Radio: An Alternative Way to Connect.

    ERIC Educational Resources Information Center

    Lucas, Larry W.

    1995-01-01

    Explains packet radio as a form of telecomputing in which digital data is transported via radio waves instead of telephone lines or other cabling, and describes how it can be used by students to access the Internet. Highlights include packet bulletin board systems and equipment needed for a packet radio station. (LRW)

  13. Making Waves: Pirate Radio and Popular Music.

    ERIC Educational Resources Information Center

    Jones, Steve

    The history of pirate radio--radio broadcasts offered by unlicensed broadcasters as alternatives to licensed, commercial radio programming--is difficult to trace, both in America and the United Kingdom (UK) since mention of pirate broadcasts of a less-then-thrilling nature are rarely found. Also, until 1927, the U.S. government did not formally…

  14. New trends in meteor radio receivers

    NASA Astrophysics Data System (ADS)

    Rault, Jean-Louis

    2014-01-01

    Recent progresses in low cost—but performing—SDR (software defined radio) technology presents a major breakthrough in the domain of meteor radio observations. Their performances are now good enough for meteor work and should therefore encourage newcomers to join the meteor radio community.

  15. 14 CFR 121.345 - Radio equipment.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Radio equipment. 121.345 Section 121.345..., FLAG, AND SUPPLEMENTAL OPERATIONS Instrument and Equipment Requirements § 121.345 Radio equipment. (a) No person may operate an airplane unless it is equipped with radio equipment required for the kind...

  16. 33 CFR 401.63 - Radio procedures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Radio procedures. 401.63 Section 401.63 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Radio Communications § 401.63 Radio procedures....

  17. 33 CFR 401.63 - Radio procedures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Radio procedures. 401.63 Section 401.63 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Radio Communications § 401.63 Radio procedures....

  18. 47 CFR 32.2231 - Radio systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Radio systems. 32.2231 Section 32.2231... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2231 Radio systems. (a) This account shall include the original cost of ownership of radio transmitters and receivers....

  19. 47 CFR 32.2231 - Radio systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Radio systems. 32.2231 Section 32.2231... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2231 Radio systems. (a) This account shall include the original cost of ownership of radio transmitters and receivers....

  20. 46 CFR 129.395 - Radio installations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Radio installations. 129.395 Section 129.395 Shipping... INSTALLATIONS Power Sources and Distribution Systems § 129.395 Radio installations. A separate circuit, with overcurrent protection at the switchboard, must be provided for at least one radio installation....

  1. 46 CFR 129.395 - Radio installations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Radio installations. 129.395 Section 129.395 Shipping... INSTALLATIONS Power Sources and Distribution Systems § 129.395 Radio installations. A separate circuit, with overcurrent protection at the switchboard, must be provided for at least one radio installation....

  2. 46 CFR 129.395 - Radio installations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Radio installations. 129.395 Section 129.395 Shipping... INSTALLATIONS Power Sources and Distribution Systems § 129.395 Radio installations. A separate circuit, with overcurrent protection at the switchboard, must be provided for at least one radio installation....

  3. 14 CFR 99.9 - Radio requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Radio requirements. 99.9 Section 99.9... AND GENERAL OPERATING RULES SECURITY CONTROL OF AIR TRAFFIC General § 99.9 Radio requirements. (a) A person who operates a civil aircraft into an ADIZ must have a functioning two-way radio, and the...

  4. 14 CFR 121.345 - Radio equipment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Radio equipment. 121.345 Section 121.345..., FLAG, AND SUPPLEMENTAL OPERATIONS Instrument and Equipment Requirements § 121.345 Radio equipment. (a) No person may operate an airplane unless it is equipped with radio equipment required for the kind...

  5. 14 CFR 99.9 - Radio requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Radio requirements. 99.9 Section 99.9... AND GENERAL OPERATING RULES SECURITY CONTROL OF AIR TRAFFIC General § 99.9 Radio requirements. (a) A person who operates a civil aircraft into an ADIZ must have a functioning two-way radio, and the...

  6. 46 CFR 169.715 - Radio.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Radio. 169.715 Section 169.715 Shipping COAST GUARD..., Miscellaneous Systems, and Equipment § 169.715 Radio. (a) Radiotelegraph and radiotelephone installations are... Regulations, part 83. (b) A valid certificate issued by the FCC is evidence that the radio installation is...

  7. 14 CFR 99.9 - Radio requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Radio requirements. 99.9 Section 99.9... AND GENERAL OPERATING RULES SECURITY CONTROL OF AIR TRAFFIC General § 99.9 Radio requirements. (a) A person who operates a civil aircraft into an ADIZ must have a functioning two-way radio, and the...

  8. 14 CFR 121.345 - Radio equipment.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Radio equipment. 121.345 Section 121.345..., FLAG, AND SUPPLEMENTAL OPERATIONS Instrument and Equipment Requirements § 121.345 Radio equipment. (a) No person may operate an airplane unless it is equipped with radio equipment required for the kind...

  9. 46 CFR 15.830 - Radio officers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Commission requirements as found in 47 CFR part 13 and 47 CFR part 80. ... 46 Shipping 1 2014-10-01 2014-10-01 false Radio officers. 15.830 Section 15.830 Shipping COAST... Computations § 15.830 Radio officers. Radio officers are required on certain merchant vessels of the...

  10. 47 CFR 32.2231 - Radio systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Radio systems. 32.2231 Section 32.2231... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2231 Radio systems. (a) This account shall include the original cost of ownership of radio transmitters and receivers....

  11. 46 CFR 169.715 - Radio.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Radio. 169.715 Section 169.715 Shipping COAST GUARD..., Miscellaneous Systems, and Equipment § 169.715 Radio. (a) Radiotelegraph and radiotelephone installations are... Regulations, part 83. (b) A valid certificate issued by the FCC is evidence that the radio installation is...

  12. 33 CFR 401.63 - Radio procedures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Radio procedures. 401.63 Section 401.63 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Radio Communications § 401.63 Radio procedures....

  13. 46 CFR 129.395 - Radio installations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Radio installations. 129.395 Section 129.395 Shipping... INSTALLATIONS Power Sources and Distribution Systems § 129.395 Radio installations. A separate circuit, with overcurrent protection at the switchboard, must be provided for at least one radio installation....

  14. 47 CFR 32.2231 - Radio systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Radio systems. 32.2231 Section 32.2231... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2231 Radio systems. (a) This account shall include the original cost of ownership of radio transmitters and receivers....

  15. 46 CFR 129.395 - Radio installations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Radio installations. 129.395 Section 129.395 Shipping... INSTALLATIONS Power Sources and Distribution Systems § 129.395 Radio installations. A separate circuit, with overcurrent protection at the switchboard, must be provided for at least one radio installation....

  16. 62. The Return of Educational Radio?

    ERIC Educational Resources Information Center

    Berman, Sally D.

    2008-01-01

    This paper examines one of the traditional technologies of distance education, radio, and presents examples of educational and community radio usage in Asia and Africa. Instead of merely transposing western approaches to distance education in developing countries, it is suggested that the developed world can learn from uses of radio in developing…

  17. 33 CFR 401.63 - Radio procedures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Radio procedures. 401.63 Section 401.63 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Radio Communications § 401.63 Radio procedures....

  18. 14 CFR 99.9 - Radio requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Radio requirements. 99.9 Section 99.9... AND GENERAL OPERATING RULES SECURITY CONTROL OF AIR TRAFFIC General § 99.9 Radio requirements. (a) A person who operates a civil aircraft into an ADIZ must have a functioning two-way radio, and the...

  19. 14 CFR 121.345 - Radio equipment.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Radio equipment. 121.345 Section 121.345..., FLAG, AND SUPPLEMENTAL OPERATIONS Instrument and Equipment Requirements § 121.345 Radio equipment. (a) No person may operate an airplane unless it is equipped with radio equipment required for the kind...

  20. 14 CFR 121.345 - Radio equipment.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Radio equipment. 121.345 Section 121.345..., FLAG, AND SUPPLEMENTAL OPERATIONS Instrument and Equipment Requirements § 121.345 Radio equipment. (a) No person may operate an airplane unless it is equipped with radio equipment required for the kind...

  1. 47 CFR 32.2231 - Radio systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Radio systems. 32.2231 Section 32.2231... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2231 Radio systems. (a) This account shall include the original cost of ownership of radio transmitters and receivers....

  2. 33 CFR 401.63 - Radio procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Radio procedures. 401.63 Section 401.63 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Radio Communications § 401.63 Radio procedures....

  3. 46 CFR 169.715 - Radio.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Radio. 169.715 Section 169.715 Shipping COAST GUARD..., Miscellaneous Systems, and Equipment § 169.715 Radio. (a) Radiotelegraph and radiotelephone installations are... Regulations, part 83. (b) A valid certificate issued by the FCC is evidence that the radio installation is...

  4. 14 CFR 99.9 - Radio requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Radio requirements. 99.9 Section 99.9... AND GENERAL OPERATING RULES SECURITY CONTROL OF AIR TRAFFIC General § 99.9 Radio requirements. (a) A person who operates a civil aircraft into an ADIZ must have a functioning two-way radio, and the...

  5. Very large radio surveys of the sky.

    PubMed

    Condon, J J

    1999-04-27

    Recent advances in electronics and computing have made possible a new generation of large radio surveys of the sky that yield an order-of-magnitude higher sensitivity and positional accuracy. Combined with the unique properties of the radio universe, these quantitative improvements open up qualitatively different and exciting new scientific applications of radio surveys. PMID:10220365

  6. Very large radio surveys of the sky

    PubMed Central

    Condon, J. J.

    1999-01-01

    Recent advances in electronics and computing have made possible a new generation of large radio surveys of the sky that yield an order-of-magnitude higher sensitivity and positional accuracy. Combined with the unique properties of the radio universe, these quantitative improvements open up qualitatively different and exciting new scientific applications of radio surveys. PMID:10220365

  7. Radio properties of Compact Steep Spectrum and GHz-Peaked Spectrum radio sources

    NASA Astrophysics Data System (ADS)

    Orienti, M.

    2016-02-01

    Compact steep spectrum (CSS) and GHz-peaked spectrum (GPS) radio sources represent a large fraction of the extragalactic objects in flux density-limited samples. They are compact, powerful radio sources whose synchrotron peak frequency ranges between a few hundred MHz to several GHz. CSS and GPS radio sources are currently interpreted as objects in which the radio emission is in an early evolutionary stage. In this contribution I review the radio properties and the physical characteristics of this class of radio sources, and the interplay between their radio emission and the ambient medium of the host galaxy.

  8. Radio spectra of intermediate-luminosity broad-line radio galaxies .

    NASA Astrophysics Data System (ADS)

    Angelakis, E.; Kadler, M.; Lewis, K.; Sambruna, R. M.; Eracleous, M.; Zensus, J. A.

    Within the context of investigating possible differences between the mechanisms at play in Radio Loud AGN and those in Radio Quiet ones, we study the spectral characteristics of a selected sample of Intermediate-Luminosity Broad-Line Radio Galaxies in X-rays, optical, IR and radio. Here, we present the radio spectra acquired with the 100-m radio telescope in Effelsberg between 2.6 and 32 GHz. These measurements reveal a large variety of spectral shapes urging for radio imaging that would disclose the source morphology. Such studies could potentially discriminate between different mechanisms.

  9. Voyager planetary radio astronomy studies

    NASA Technical Reports Server (NTRS)

    Staelin, David H.; Eikenberry, Stephen S.

    1993-01-01

    Analysis of nonthermal radio emission data obtained by the Planetary Radio Astronomy (PRA) spectrometers on the Voyager 1 and 2 spacecraft was performed. This PRA data provided unique insights into the radio emission characteristics of the outer planets because of PRA's unique spectral response below the terrestrial ionospheric plasma frequency and its unprecedented proximity to the source. Of those results which were documented or published, this final report surveys only the highlights and cites references for more complete discussions. Unpublished results for Uranus, Neptune, and theoretical Ionian current distributions are presented at greater length. The most important conclusion to be drawn from these observations is that banded spectral emission is common to the radio emission below 1-2 MHz observed from all four Jovian planets. In every case multiple spectral features evolve on time scales of seconds to minutes. To the extent these features drift in frequency, they appear never to cross one another. The Neptunian spectral features appear to drift little or not at all, their evolution consisting principally of waxing and waning. Since other evidence strongly suggests that most or all of this radio emission is occurring near the local magnetospheric electron cyclotron frequency, this implies that this emission preferentially occurs at certain continually changing planetary radii. It remains unknown why certain radii might be favored, unless radial electric field components or other means serve to differentiate radially the magnetospheric plasma density, particle energy vectors, or particle coherence. Calculation of the spatial distribution and intensity of the Io-generated magnetospheric currents are also presented; these currents may be limited principally by wave impedance and local field strengths.

  10. The Role of Alternative Programming in College Radio.

    ERIC Educational Resources Information Center

    Sauls, Samuel J.

    College radio is quite often viewed as the true alternative to commercial radio. However, what is alternative radio and how does college radio factor into the ideal? To further understand this concept, this paper focuses on the role of alternative programming in college radio. Areas discussed include alternative radio as a non-mainstream form of…

  11. Radios in the Classroom: Curriculum Integration and Communication Skills.

    ERIC Educational Resources Information Center

    Ninno, Anton

    2000-01-01

    Describes radio applications for education and summarizes radio activities for elementary and secondary school classrooms. Discusses teaching the history of radio communications; AM-FM radio; international shortwave broadcasts; NOAA (National Oceanic and Atmospheric Administration) weather service broadcasts; scanner radios; and amateur radios.…

  12. Radio Astronomy Explorer (RAE) 1 observations of terrestrial radio noise

    NASA Technical Reports Server (NTRS)

    Herman, J. R.; Caruso, J. A.

    1971-01-01

    Radio Astonomy Explorer (RAE) 1 data are analyzed to establish characteristics of HF terrestrial radio noise at an altitude of about 6000 km. Time and frequency variations in amplitude of the observed noise well above cosmic noise background are explained on the basis of temporal and spatial variations in ionospheric critical frequency coupled with those in noise source distributions. It is shown that terrestrial noise regularly breaks through the ionosphere and reaches RAE with magnitudes 15 or more db higher than cosmic noise background. Maximum terrestrial noise is observed when RAE is over the dark side of the Earth in the neighborhood of equatorial continental land masses where thunderstorms occur most frequently. The observed noise level is 30-40 db lower with RAE over oceans.

  13. Solar radio observations and radio interference monitoring in Roztoky

    NASA Astrophysics Data System (ADS)

    Monstein, C.; Baluďanský, D.

    2013-10-01

    This paper is part of a planned measurement campaign in which spectrum measurements were carried out at different locations worldwide within potential locations of the e-Callisto network. The results of measurements at the Callisto observing station in Roztoky, which took place at the beginning of May 2013, are presented. Measurements were made out with a special low cost broadband logarithmic periodic antenna connected to a Callisto spectrometer designed and built at ETH Zurich (Benz, 2004). This study provides the technical basis to decide whether it is possible to make solar spectroscopic measurements below 1 GHz (λ>30 cm) at the observing station. In terms of electromagnetic interference, Roztoky is not perfect for broadband spectroscopic solar radio astronomy observations due to non negligible radio interference level from the nearby FM-transmitters. Nevertheless, low frequency observations below 80 MHz, as well as observations in some small bands above 116 MHz can be done.

  14. EARS, MARS combined radio observations - 2014

    NASA Astrophysics Data System (ADS)

    Tomezzoli, Giancarlo

    2014-02-01

    The Lyrid meteor shower was generated on 21-22 April 2014 by the passage of the Earth through the path of the debris of the comet C/1861 G1 (Thatcher). The Camelopardalids meteor shower was generated on 23-24 May 2014 by the passage of the Earth through the path of the debris of the comet 209P/Linear. The EurAstro Radio Station (EARS) and the Malta Astro Radio Station (MARS) were operated in parallel for two combined radio observation campaigns. The campaigns revealed that further combined radio observation campaigns are necessary to solve the problem of estimating the number of lost radio meteor echoes.

  15. HIGH CURRENT RADIO FREQUENCY ION SOURCE

    DOEpatents

    Abdelaziz, M.E.

    1963-04-01

    This patent relates to a high current radio frequency ion source. A cylindrical plasma container has a coil disposed around the exterior surface thereof along the longitudinal axis. Means are provided for the injection of an unionized gas into the container and for applying a radio frequency signal to the coil whereby a radio frequency field is generated within the container parallel to the longitudinal axis thereof to ionize the injected gas. Cathode and anode means are provided for extracting transverse to the radio frequency field from an area midway between the ends of the container along the longitudinal axis thereof the ions created by said radio frequency field. (AEC)

  16. Contribution to the diffuse radio background from extragalactic radio sources

    NASA Astrophysics Data System (ADS)

    Vernstrom, T.; Scott, Douglas; Wall, J. V.

    2011-08-01

    We examine the brightness of the cosmic radio background (CRB) by comparing the contribution from individual source counts to absolute measurements. We use a compilation of radio counts to estimate the contribution of detected sources to the CRB in several different frequency bands. Using a Monte Carlo Markov chain technique, we estimate the brightness values and uncertainties, paying attention to various sources of systematic error. At ν= 150, 325, 408, 610, 1.4, 4.8 and 8.4 GHz, our calculated contributions to the background sky temperature are 18, 2.8, 1.6, 0.71, 0.11, 0.0032 and 0.0059 K, respectively. We then compare our results to absolute measurements from the Absolute Radiometer for Cosmology, Astrophysics and Diffuse Emission (ARCADE 2) experiment. If the ARCADE 2 measurements are correct and come from sources, then there must be an additional population of radio galaxies, fainter than where current data are probing. More specifically, the Euclidean-normalized counts at 1.4 GHz have to have an additional bump below about 10 μJy.

  17. Radio Losses for Concatenated Codes

    NASA Astrophysics Data System (ADS)

    Shambayati, S.

    2002-07-01

    The advent of higher powered spacecraft amplifiers and better ground receivers capable of tracking spacecraft carrier signals with narrower loop bandwidths requires better understanding of the carrier tracking loss (radio loss) mechanism of the concatenated codes used for deep-space missions. In this article, we present results of simulations performed for a (7,1/2), Reed-Solomon (255,223), interleaver depth-5 concatenated code in order to shed some light on this issue. Through these simulations, we obtained the performance of this code over an additive white Gaussian noise (AWGN) channel (the baseline performance) in terms of both its frame-error rate (FER) and its bit-error rate at the output of the Reed-Solomon decoder (RS-BER). After obtaining these results, we curve fitted the baseline performance curves for FER and RS-BER and calculated the high-rate radio losses for this code for an FER of 10^(-4) and its corresponding baseline RS-BER of 2.1 x 10^(-6) for a carrier loop signal-to-noise ratio (SNR) of 14.8 dB. This calculation revealed that even though over the AWGN channel the FER value and the RS-BER value correspond to each other (i.e., these values are obtained by the same bit SNR value), the RS-BER value has higher high-rate losses than does the FER value. Furthermore, this calculation contradicted the previous assumption th at at high data rates concatenated codes have the same radio losses as their constituent convolutional codes. Our results showed much higher losses for the FER and the RS-BER (by as much as 2 dB) than for the corresponding baseline BER of the convolutional code. Further simulations were performed to investigate the effects of changes in the data rate on the code's radio losses. It was observed that as the data rate increased the radio losses for both the FER and the RS-BER approached their respective calculated high-rate values. Furthermore, these simulations showed that a simple two-parameter function could model the increase in the

  18. 47 CFR 95.201 - (R/C Rule 1) What is the Radio Control (R/C) Radio Service?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false (R/C Rule 1) What is the Radio Control (R/C) Radio Service? 95.201 Section 95.201 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Radio Control (R/C) Radio Service...

  19. 47 CFR 95.201 - (R/C Rule 1) What is the Radio Control (R/C) Radio Service?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false (R/C Rule 1) What is the Radio Control (R/C) Radio Service? 95.201 Section 95.201 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Radio Control (R/C) Radio Service...

  20. 47 CFR 95.201 - (R/C Rule 1) What is the Radio Control (R/C) Radio Service?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false (R/C Rule 1) What is the Radio Control (R/C) Radio Service? 95.201 Section 95.201 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Radio Control (R/C) Radio Service...

  1. 47 CFR 95.201 - (R/C Rule 1) What is the Radio Control (R/C) Radio Service?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false (R/C Rule 1) What is the Radio Control (R/C) Radio Service? 95.201 Section 95.201 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Radio Control (R/C) Radio Service...

  2. 47 CFR 95.201 - (R/C Rule 1) What is the Radio Control (R/C) Radio Service?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false (R/C Rule 1) What is the Radio Control (R/C) Radio Service? 95.201 Section 95.201 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Radio Control (R/C) Radio Service...

  3. Radio detections of southern ultracool dwarfs

    NASA Astrophysics Data System (ADS)

    Lynch, C.; Murphy, T.; Ravi, V.; Hobbs, G.; Lo, K.; Ward, C.

    2016-04-01

    We report the results of a volume-limited survey using the Australia Telescope Compact Array to search for transient and quiescent radio emission from 15 Southern hemisphere ultracool dwarfs. We detect radio emission from 2MASSW J0004348-404405 increasing the number of radio loud ultracool dwarfs to 22. We also observe radio emission from 2MASS J10481463-3956062 and 2MASSI J0339352-352544, two sources with previous radio detections. The radio emission from the three detected sources shows no variability or flare emission. Modelling this quiescent emission we find that it is consistent with optically thin gyrosynchrotron emission from a magnetosphere with an emitting region radius of (1-2)R*, magnetic field inclination 20°-80°, field strength ˜10-200 G, and power-law electron density ˜104-108 cm-3. Additionally, we place upper limits on four ultracool dwarfs with no previous radio observations. This increases the number of ultracool dwarfs studied at radio frequencies to 222. Analysing general trends of the radio emission for this sample of 15 sources, we find that the radio activity increases for later spectral types and more rapidly rotating objects. Furthermore, comparing the ratio of the radio to X-ray luminosities for these sources, we find 2MASS J10481463-3956062 and 2MASSI J0339352-352544 violate the Güdel-Benz relation by more than two orders of magnitude.

  4. Radio Frequency Power Load and Associated Method

    NASA Technical Reports Server (NTRS)

    Srinivasan, V. Karthik (Inventor); Freestone, Todd M. (Inventor); Sims, William Herbert, III (Inventor)

    2014-01-01

    A radio frequency power load and associated method. A radio frequency power load apparatus may include a container with an ionized fluid therein. The apparatus may include one conductor immersed in a fluid and another conductor electrically connected to the container. A radio frequency transmission system may include a radio frequency transmitter, a radio frequency amplifier connected to the transmitter and a radio frequency power load apparatus connected to the amplifier. The apparatus may include a fluid having an ion source therein, one conductor immersed in a fluid, and another conductor electrically connected to the container. A method of dissipating power generated by a radio frequency transmission system may include constructing a waveguide with ionized fluid in a container and connecting the waveguide to an amplifier of the transmission system.

  5. SDR - radio meteor affordable approach

    NASA Astrophysics Data System (ADS)

    Lesanu, C.; Dragoiu, A.

    2012-01-01

    A software-defined radio system, or SDR, is a radio communication system where components that have been typically implemented in hardware (e.g., mixers, filters, amplifiers, modulators/ demodulators, detectors, etc.) are instead implemented by means of software on an embedded computing device or a personal computer. While the concept of SDR is not new, the rapidly evolving capabilities of digital electronics render practical many processes which used to be only theoretically possible. A basic SDR system may consist of a personal computer equipped with a sound card, or other analog-to-digital converter, preceded by some form of RF front end. Significant amounts of signal processing are handed over to the general-purpose processor, rather than being done in special-purpose hardware.

  6. The development of radio engineering

    NASA Astrophysics Data System (ADS)

    Trenkle, F.

    1982-11-01

    A review is provided of the development of radio engineering in Germany during the time period from 1897 to 1969, when sections of the German Experimental Institute for Aviation were incorporated into the 'German Research and Experimental Institute for Aeronautics and Astronautics. Techniques for radiotelephony communication between airships, aircraft, and ground stations were established during the period from 1897 to 1918. Developments occurring during the time from 1919 to 1937 are related to fundamental investigations regarding the behavior of electromagnetic waves, methods for the remote control of vehicles, position finding techniques, and approaches for making the landing of airships under conditions of poor visibility possible. Navigation methods and long-range radio communication were developed during the time from 1927 to 1945.

  7. Uranus as a radio source

    NASA Technical Reports Server (NTRS)

    Desch, M. D.; Kaiser, M. L.; Zarka, P.; Lecacheux, A.; Leblanc, Y.; Aubier, M.; Ortega-Molina, A.

    1991-01-01

    The complex nature of the Uranus radio emissions, both magnetospheric and atmospheric, is reviewed, with emphasis on the identification of distinct components and the determination of their source locations. Seven radii components were discovered in addition to the RF signature of lightning in the planet's atmosphere. Six of the seven magnetospheric components are freely propagating emissions; one component, the nonthermal continuum, is trapped in the density cavity between the magnetopause and the dense inner magnetosphere. The radio components are divided into two types according to their emission signature: bursty emission and smooth emission. The inferred source location for the dominant nightside emission is above the nightside magnetic pole, largely overlapping the UV auroral region and the magnetic polar cap. The N-burst component appears to be associated with solar-wind enhancements at Uranus, consistent with the idea that the solar wind was triggering magnetospheric substormlike activity during the encounter.

  8. Precision Geodesy via Radio Interferometry.

    PubMed

    Hinteregger, H F; Shapiro, I I; Robertson, D S; Knight, C A; Ergas, R A; Whitney, A R; Rogers, A E; Moran, J M; Clark, T A; Burke, B F

    1972-10-27

    Very-long-baseline interferometry experiments, involving observations of extragalactic radio sources, were performed in 1969 to determine the vector separations between antenna sites in Massachusetts and West Virginia. The 845.130-kilometer baseline was estimated from two separate experiments. The results agreed with each other to within 2 meters in all three components and with a special geodetic survey to within 2 meters in length; the differences in baseline direction as determined by the survey and by interferometry corresponded to discrepancies of about 5 meters. The experiments also yielded positions for nine extragalactic radio sources, most to within 1 arc second, and allowed the hydrogen maser clocks at the two sites to be synchronized a posteriori with an uncertainty of only a few nanoseconds. PMID:17815361

  9. The Giant Metrewave Radio Telescope

    NASA Astrophysics Data System (ADS)

    Nityananda, R.

    2003-05-01

    The Giant Metrewave Radio Telescope (GMRT) of the National Centre of Radio Astrophysics (NCRA) of the Tata Institute of Fundamental Research (TIFR) at Khodad, India, has been operational in the band 0.2 to 2 metres for the last two and a half years. The system characteristics and performance and recent results from the group will be presented. Details of use over the last six months by scientists from other observatories under the GMRT Time Allocation Committee (GTAC) and future plans will be also be reviewed in this paper. Areas which have been studied include observations made in the GMRT band of neutral hydrogen, nearby galaxies, supernova remnants, the Galactic Centre, pulsars, the Sun and others.

  10. Lunar Interferometric Radio Array: LIRA

    NASA Astrophysics Data System (ADS)

    Abbott, J.; Pixton, S.; Roberts, C.; Reyhanoglu, M.

    2000-01-01

    The Lunar Interferometric Radio Array (LIRA) is a performance driven design, with emphasis on utilizing the unique attributes of the far-side of the moon as a platform for radio astronomy. LIRA consists of three independent Lunar Telescope Units (LTUs), autonomously landed on the moon, and a communications relay satellite orbiting at libration point two (L2). Each LTU deploys a large inflatable spheroid, whose underside has been impregnated with a reflective coating. The spheroid is then gradually hardened into a shell by the suns ultraviolet radiation. LIRA achieves broadband capabilities by operating each LTU independently (tuned to offset frequencies), or provides high resolution observations as a three-element interferometer. The interferometer is functional with as few as two elements, yet will achieve greater resolution with additional elements. Thus, LIRA delivers both redundancy and the possibility for future expansion. Data processing, including interferometric synthesis, occurs at an earth-based ground station, eliminating the need for complex onboard data manipulation.

  11. The radio telescope RATAN 600

    NASA Technical Reports Server (NTRS)

    Schwartz, R.

    1978-01-01

    A six-meter radio antenna having 900 reflector elements arranged on a 579 -meter diameter circle and located in the northern part of the Caucasian Mountains is described. The elements are about 7.4 m by 2 m resulting in a total reflector surface of about 10,000 sq m. Individual elements can be adjusted by changing 260 screws and can be rotated both horizontally and vertically as well as being moved translationally in the radial direction. The circular area is equipped with a grid of tracks where four asymmetric cylindrical paraboloids serving as subreflectors are located. The directional profile or observational direction of the antenna is achieved by shifting the subreflectors and changing the position of the reflecting elements with respect to the subreflectors. Different radio sources can be observed at the same time by using different subreflectors and their associated reflector sectors. Each subreflector is connected to a receiving station. Capabilities for spectroscopic observation are discussed.

  12. Very high redshift radio galaxies

    SciTech Connect

    van Breugel, W.J.M., LLNL

    1997-12-01

    High redshift radio galaxies (HzRGs) provide unique targets for the study of the formation and evolution of massive galaxies and galaxy clusters at very high redshifts. We discuss how efficient HzRG samples ae selected, the evidence for strong morphological evolution at near-infracd wavelengths, and for jet-induced star formation in the z = 3 800 HzRG 4C41 17

  13. Low Frequency Radio Experiment (LORE)

    NASA Astrophysics Data System (ADS)

    Manoharan, Periasamy K.; Joshi, Bhal Chandra; Naidu, Arun Kumar

    High temporal and frequency resolution observations of solar generated disturbances below 15 MHz in the near-Sun region and at Sun-Earth distances in conjunction with optical and high energy observations of Sun are essential to understand the structure and evolution of eruptions, such as, flares, coronal mass ejections (CMEs), and their associated solar wind disturbances at heights above the photosphere and their consequences in the interplanetary medium. This talk presents a case study of Low Frequency Radio Experiment (LORE) payload to probe the corona and the solar disturbances at solar offsets greater than 2 solar radii below 30 MHz. The LORE, although not part of Aditya-L1 mission, can be complimentary to planned Aditya-L1 coronagraph and its other on-board payloads as well as synergistic to ground based observations, which are routinely carried out by Ooty Radio Telescope. We discuss the baseline design and technical details of the proposed LORE and it is particularly suitable for providing data on the detailed time and frequency structure of fast drifting Type-III and slow drifting Type-II radio bursts with unprecedented time and frequency resolution as well as goniopolarimetry, made possible with better designed antennas and state-of-art electronics, employing FPGAs and an intelligent data management system. This would enable wide ranging studies such as studies of nonlinear plasma processes, CME in-situ radio emission, CME driven phenomena, interplanetary CME driven shocks, ICMEs driven by decelerating IP shocks and space weather effects of Solar Wind interaction regions. The talk will highlight the science objectives as well as the proposed technical design features.

  14. Radio frequency coaxial feedthrough device

    DOEpatents

    Owens, Thomas L.; Baity, Frederick W.; Hoffman, Daniel J.; Whealton, John H.

    1987-01-01

    A radio frequency coaxial vacuum feedthrough is provided which utilizes a cylindrical ceramic vacuum break formed of an alumina ceramic. The cylinder is coaxially disposed and brazed between tapered coaxial conductors to form a vacuum sealed connection between a pressurized upstream coaxial transmission line and a utilization device located within a vacuum container. The feedthrough provides 50 ohm matched impedance RF feedthrough up to about 500 MHz at power levels in the multimegawatt range.

  15. Advances in solar radio astronomy

    NASA Technical Reports Server (NTRS)

    Kundu, M. R.

    1982-01-01

    The status of the observations and interpretations of the sun's radio emission covering the entire radio spectrum from millimeter wavelengths to hectometer and kilometer wavelengths is reviewed. Emphasis is given to the progress made in solar radio physics as a result of recent advances in plasma and radiation theory. It is noted that the capability now exists of observing the sun with a spatial resolution of approximately a second of arc and a temporal resolution of about a millisecond at centimeter wavelengths and of obtaining fast multifrequency two-dimensional pictures of the sun at meter and decameter wavelengths. A summary is given of the properties of nonflaring active regions at millimeter, centimeter, and meter-decameter wavelengths. The properties of centimeter wave bursts are discussed in connection with the high spatial resolution observations. The observations of the preflare build-up of an active region are reviewed. High spatial resolution observations (a few seconds of arc to approximately 1 arcsec) are discussed, with particular attention given to the one- and two-dimensional maps of centimeter-wavelength burst sources.

  16. Radio and optical interferometric imaging

    NASA Technical Reports Server (NTRS)

    Cornwell, Tim J.

    1992-01-01

    Since diffraction-limited imaging with a single aperture yields angular resolution approx. lambda/D, the attainment of high angular resolution with single apertures requires the construction of correspondingly large monolithic apertures, the whole surface of which must be figured to much less than a wavelength. At the longer wavelengths, it is impossible to build a sufficiently large single aperture: for example, at lambda 21 cm, arcsec resolution requires an aperture of diameter approx. 50 km. At the shorter wavelengths, the atmosphere imposes a natural limit in resolution of about one arcsec. However, another route is possible; that is, using synthetic apertures to image the sky. Synthetic apertures are now in use in many fields, e.g., radio interferometry, radar imaging, and magnetic-resonance imaging. Radio-interferometric techniques developed in radio astronomy over the past 40 years are now being applied to optical and IR astronomical imaging by a number of groups. Furthermore, the problem of figuring synthetic apertures is considerably simpler, and can be implemented in a computer: new 'self-calibration' techniques allow imaging even in the presence of phase errors due to the atmosphere.

  17. AO Observations of Three Powerful Radio Galaxies

    SciTech Connect

    de Vries, W; van Bruegel, W; Quirrenbach, A

    2002-08-01

    The host galaxies of powerful radio sources are ideal laboratories to study active galactic nuclei (AGN). The galaxies themselves are among the most massive systems in the universe, and are believed to harbor supermassive black holes (SMBH). If large galaxies are formed in a hierarchical way by multiple merger events, radio galaxies at low redshift represent the end-products of this process. However, it is not clear why some of these massive ellipticals have associated radio emission, while others do not. Both are thought to contain SMBHs, with masses proportional to the total luminous mass in the bulge. It either implies every SMBH has recurrent radio-loud phases, and the radio-quiet galaxies happen to be in the ''low'' state, or that the radio galaxy nuclei are physically different from radio-quiet ones, i.e. by having a more massive SMBH for a given bulge mass. Here we present the first results from our adaptive optics imaging and spectroscopy pilot program on three nearby powerful radio galaxies. Initiating a larger, more systematic AO survey of radio galaxies (preferentially with Laser Guide Star equipped AO systems) has the potential of furthering our understanding of the physical properties of radio sources, their triggering, and their subsequent evolution.

  18. Radio Variability Properties of a Sample of 168 Radio Sources: Periodicity Analysis

    NASA Astrophysics Data System (ADS)

    Fan, J. H.; Liu, Y.; Yuan, Y. H.; Wang, H. G.; Wang, Y. X.; Gupta, A. C.; Yang, J. H.; Li, J.; Zhou, J. L.; Xu, S. X.; Chen, J. L.; Liu, F.; Li, Y. Z.

    2006-12-01

    In this work, using the data base at the University of Michigan Radio Astronomy Observatory (UMRAO) at 8 GHz, we investigated the possible periodicity in the radio light curves using Jurkevich analysis method. The results show that the radio sources display a possibly physically significant periodicity in a range of 0.08 to 14.5 years. Besides, the radio spectral indexes are also calculated, the results show that the averaged radio spectral index is α4.814.5=-0.15 (fν ∝να) for flat spectrum radio quasars (FSRQs) and α4.814.5=0.01 for BL Lacertae objects. Some discussions are included.

  19. Sources of the Radio Background Considered

    SciTech Connect

    Singal, J.; Stawarz, L.; Lawrence, A.; Petrosian, V.; /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.

    2011-08-22

    We investigate possible origins of the extragalactic radio background reported by the ARCADE 2 collaboration. The surface brightness of the background is several times higher than that which would result from currently observed radio sources. We consider contributions to the background from diffuse synchrotron emission from clusters and the intergalactic medium, previously unrecognized flux from low surface brightness regions of radio sources, and faint point sources below the flux limit of existing surveys. By examining radio source counts available in the literature, we conclude that most of the radio background is produced by radio point sources that dominate at sub {mu}Jy fluxes. We show that a truly diffuse background produced by elections far from galaxies is ruled out because such energetic electrons would overproduce the observed X-ray/{gamma}-ray background through inverse Compton scattering of the other photon fields. Unrecognized flux from low surface brightness regions of extended radio sources, or moderate flux sources missed entirely by radio source count surveys, cannot explain the bulk of the observed background, but may contribute as much as 10%. We consider both radio supernovae and radio quiet quasars as candidate sources for the background, and show that both fail to produce it at the observed level because of insufficient number of objects and total flux, although radio quiet quasars contribute at the level of at least a few percent. We conclude that the most important population for production of the background is likely ordinary starforming galaxies above redshift 1 characterized by an evolving radio far-infrared correlation, which increases toward the radio loud with redshift.

  20. Fast Radio Bursts and Radio Transients from Black Hole Batteries

    NASA Astrophysics Data System (ADS)

    Mingarelli, Chiara M. F.; Levin, Janna; Lazio, T. Joseph W.

    2015-12-01

    Most black holes (BHs) will absorb a neutron star (NS) companion fully intact without tidal disruption, suggesting the pair will remain dark to telescopes. Even without tidal disruption, electromagnetic (EM) luminosity is generated from the battery phase of the binary when the BH interacts with the NS magnetic field. Originally, the luminosity was expected to be in high-energy X-rays or gamma-rays, however, we conjecture that some of the battery power is emitted in the radio bandwidth. While the luminosity and timescale are suggestive of fast radio bursts (FRBs; millisecond-scale radio transients) NS-BH coalescence rates are too low to make these a primary FRB source. Instead, we propose that the transients form a FRB sub-population, distinguishable by a double peak with a precursor. The rapid ramp-up in luminosity manifests as a precursor to the burst which is 20%-80% as luminous given 0.5 ms timing resolution. The main burst arises from the peak luminosity before the merger. The post-merger burst follows from the NS magnetic field migration to the BH, causing a shock. NS-BH pairs are especially desirable for ground-based gravitational wave (GW) observatories since the pair might not otherwise be detected, with EM counterparts greatly augmenting the scientific leverage beyond the GW signal. The EM signal’s ability to break degeneracies in the parameters encoded in the GW and probe the NS magnetic field strength is quite valuable, yielding insights into open problems in NS magnetic field decay.

  1. Fast Radio Bursts and Radio Transients from Black Hole Batteries

    NASA Astrophysics Data System (ADS)

    Mingarelli, Chiara M. F.; Levin, Janna; Lazio, T. Joseph W.

    2015-12-01

    Most black holes (BHs) will absorb a neutron star (NS) companion fully intact without tidal disruption, suggesting the pair will remain dark to telescopes. Even without tidal disruption, electromagnetic (EM) luminosity is generated from the battery phase of the binary when the BH interacts with the NS magnetic field. Originally, the luminosity was expected to be in high-energy X-rays or gamma-rays, however, we conjecture that some of the battery power is emitted in the radio bandwidth. While the luminosity and timescale are suggestive of fast radio bursts (FRBs; millisecond-scale radio transients) NS–BH coalescence rates are too low to make these a primary FRB source. Instead, we propose that the transients form a FRB sub-population, distinguishable by a double peak with a precursor. The rapid ramp-up in luminosity manifests as a precursor to the burst which is 20%–80% as luminous given 0.5 ms timing resolution. The main burst arises from the peak luminosity before the merger. The post-merger burst follows from the NS magnetic field migration to the BH, causing a shock. NS–BH pairs are especially desirable for ground-based gravitational wave (GW) observatories since the pair might not otherwise be detected, with EM counterparts greatly augmenting the scientific leverage beyond the GW signal. The EM signal’s ability to break degeneracies in the parameters encoded in the GW and probe the NS magnetic field strength is quite valuable, yielding insights into open problems in NS magnetic field decay.

  2. Radio frequency overview of the high explosive radio telemetry project

    SciTech Connect

    Bracht, R.; Dimsdle, J.; Rich, D.; Smith, F.

    1998-12-31

    High explosive radio telemetry (HERT) is a project that is being developed jointly by Los Alamos National Laboratory and AlliedSignal Federal Manufacturing and Technologies. The ultimate goal is to develop a small, modular telemetry system capable of high-speed detection of explosive events, with an accuracy on the order of 10 nanoseconds. The reliable telemetry of this data, from a high-speed missile trajectory, is a very challenging opportunity. All captured data must be transmitted in less than 20 microseconds of time duration. This requires a high bits/Hertz microwave telemetry modulation code to insure transmission of the data with the limited time interval available.

  3. Radio Galaxy Zoo: host galaxies and radio morphologies derived from visual inspection

    NASA Astrophysics Data System (ADS)

    Banfield, J. K.; Wong, O. I.; Willett, K. W.; Norris, R. P.; Rudnick, L.; Shabala, S. S.; Simmons, B. D.; Snyder, C.; Garon, A.; Seymour, N.; Middelberg, E.; Andernach, H.; Lintott, C. J.; Jacob, K.; Kapińska, A. D.; Mao, M. Y.; Masters, K. L.; Jarvis, M. J.; Schawinski, K.; Paget, E.; Simpson, R.; Klöckner, H.-R.; Bamford, S.; Burchell, T.; Chow, K. E.; Cotter, G.; Fortson, L.; Heywood, I.; Jones, T. W.; Kaviraj, S.; López-Sánchez, Á. R.; Maksym, W. P.; Polsterer, K.; Borden, K.; Hollow, R. P.; Whyte, L.

    2015-11-01

    We present results from the first 12 months of operation of Radio Galaxy Zoo, which upon completion will enable visual inspection of over 170 000 radio sources to determine the host galaxy of the radio emission and the radio morphology. Radio Galaxy Zoo uses 1.4 GHz radio images from both the Faint Images of the Radio Sky at Twenty Centimeters (FIRST) and the Australia Telescope Large Area Survey (ATLAS) in combination with mid-infrared images at 3.4 μm from the Wide-field Infrared Survey Explorer (WISE) and at 3.6 μm from the Spitzer Space Telescope. We present the early analysis of the WISE mid-infrared colours of the host galaxies. For images in which there is >75 per cent consensus among the Radio Galaxy Zoo cross-identifications, the project participants are as effective as the science experts at identifying the host galaxies. The majority of the identified host galaxies reside in the mid-infrared colour space dominated by elliptical galaxies, quasi-stellar objects and luminous infrared radio galaxies. We also find a distinct population of Radio Galaxy Zoo host galaxies residing in a redder mid-infrared colour space consisting of star-forming galaxies and/or dust-enhanced non-star-forming galaxies consistent with a scenario of merger-driven active galactic nuclei (AGN) formation. The completion of the full Radio Galaxy Zoo project will measure the relative populations of these hosts as a function of radio morphology and power while providing an avenue for the identification of rare and extreme radio structures. Currently, we are investigating candidates for radio galaxies with extreme morphologies, such as giant radio galaxies, late-type host galaxies with extended radio emission and hybrid morphology radio sources.

  4. Radio luminosity function of brightest cluster galaxies

    NASA Astrophysics Data System (ADS)

    Yuan, Z. S.; Han, J. L.; Wen, Z. L.

    2016-08-01

    By cross-matching the currently largest optical catalogue of galaxy clusters and the NVSS radio survey data base, we obtain a large complete sample of brightest cluster galaxies (BCGs) in the redshift range of 0.05 < z ≤ 0.45, which have radio emission and redshift information. We confirm that more powerful radio BCGs tend to be these optically very bright galaxies located in more relaxed clusters. We derived the radio luminosity functions of the largest sample of radio BCGs, and find that the functions depend on the optical luminosity of BCGs and the dynamic state of galaxy clusters. However, the radio luminosity function does not show significant evolution with redshift.

  5. Interpretation of cosmological information on radio sources

    NASA Technical Reports Server (NTRS)

    Burbidge, G.

    1977-01-01

    The question of whether any cosmological information can be obtained from radio astronomy is considered. Specific attention is given to the discovery and cosmological interpretation of the microwave background radiation, attempts to derive a Hubble relation for the optical objects identified with radio sources, searches for relations between the angular diameters of radio sources and the redshifts of their optically identified counterparts as well as between angular diameter and radio flux, construction of log N - log S curves, and luminosity volume tests. A brief outline is given of the situation that might prevail if a significant population of radio sources is not at great distances and is associated with QSOs that have been ejected from relatively nearby galaxies. It is concluded that: (1) some types of cosmological investigations have been premature; (2) much of the discussion in this area still depends on the distances of QSOs; and (3) there is no conclusive proof that the population of radio sources is changing with epoch.

  6. The Golden Years of Radio Astronomy

    NASA Astrophysics Data System (ADS)

    Kellermann, Kenneth I.

    2016-01-01

    The 1960s were the Golden Years of Radio Astronomy. During this decade a new generation of young scientists discovered quasars, pulsars, the cosmic microwave background, cosmic masers, giant molecular clouds, radio source variability, superluminal motion, radio recombination lines, the rotation of Mercury and Venus, the Venus Greenhouse effect, Jupiter's radiation belts, and opened up the high redshift Universe. On the technical side, the 1960s saw the completion of the NRAO 140-ft and 300-ft radio telescopes, the Haystack, Arecibo and Parkes antennas, the Owens Valley Interferometer, the first practical demonstrations of aperture synthesis, VLBI, and CLEAN, the Cambridge 1-mile radio telescope, the most precise tests of GR light bending, and the introduction of the 4th test of GR. Following sessions at the recent IAU 29th General Assembly on the "Golden Years of Radio Astronomy," we will discuss the circumstances surrounding these transformational discoveries which changed the course of modern astronomy.

  7. Oscar satellites, amateur radio in space

    NASA Astrophysics Data System (ADS)

    Henry, J. M.

    The history of amateur radio satellites is reviewed. Attention is given to the Canadian role in the development of the Orbiting Satellite Carrying Amateur Radio OSCAR payload carried aboard the Discoverer 36 satellite. Recent progress in developing new generation amateur radio satellites is addressed with reference to the AMSAT satellite which will retransmit emergency location transmitter signals from aircraft in distress. The position of the ELT is determined by computer processing of doppler information.

  8. Detection of Radio Transients from Supernovae

    NASA Astrophysics Data System (ADS)

    Schmitt, Christian

    2011-05-01

    A core-collapse supernova (SN) would produce an expanding shell of charged particles which interact with the surrounding magnetic field of the progenitor star producing a transient radio pulse. Approximately one supernova event per century is expected in a galaxy. The radio waves emitted are detectable by a new generation of low-frequency radio telescope arrays. We present details of an ongoing search for such events by the Eight-meter-wavelength Transient Array (ETA) and the Long Wavelength Array (LWA).

  9. Division B Commission 40: Radio Astronomy

    NASA Astrophysics Data System (ADS)

    Chapman, Jessica M.; Giovaninni, Gabriele; Taylor, Russell; Carilli, Christopher; Hills, Richard; Hirabayashi, Hisashi; Jonas, Justin L.; Lazio, Joseph; Morganti, Rafaella; Nan, Rendong; Rubio, Monica; Shastri, Prjaval; Kellermann, Ken; Ekers, Ronald; Ohishi, Masatoshi

    2016-04-01

    IAU Commission 40 for Radio Astronomy (hereafter C40) brought together scientists and engineers who carry out observational and theoretical research in radio astronomy and who develop and operate the ground and space-based radio astronomy facilities and instrumentation. As of June 2015, the Commission had approximately 1,100 members from 49 countries, corresponding to nearly 10 per cent of the total IAU membership.

  10. Radio structures in QSO-galaxy pairs

    NASA Technical Reports Server (NTRS)

    Akujor, Chidi E.

    1990-01-01

    It is now generally agreed that if quasars and nearby low redshift galaxies are associated, then there should be luminous connections between them. However, most of the observational evidence being presented is in the optical domain, whereas such evidence should also exist at radio frequencies. The author is, therefore, investigating some quasar-galaxy pairs at radio frequencies to search for luminous connections and other structural peculiarities. Radio maps of some of these sources are presented.

  11. Fast Radio Bursts and Radio Transients from Black Hole Batteries

    NASA Astrophysics Data System (ADS)

    Mingarelli, Chiara; Levin, Janna; Lazio, Joseph

    2016-03-01

    Most black holes (BHs) will absorb a neutron star (NS) companion fully intact, without tidal disruption, suggesting the pair will remain dark to telescopes. Even without tidal disruption, electromagnetic (EM) luminosity is generated from the battery phase of the binary when the BH interacts with the NS magnetic field. Originally the luminosity was expected in high-energy X-rays or gamma-rays, however we conjecture that some of the battery power is emitted in the radio bandwidth. While the luminosity and timescale are suggestive of fast radio bursts (FRBs), NS-BH coalescence rates are too low to make these a primary FRB source. Instead, we propose the transients form a FRB sub-population, distinguishable by a double peak. The main burst is from the peak luminosity before merger, while the post-merger burst follows from the NS magnetic field migration to the BH, causing a shock. NS-BH pairs are desirable for ground-based gravitational wave (GW) observatories since the pair might not be detected any other way, with EM counterparts augmenting the scientific leverage beyond the GW signal. Valuably, EM signal can break degeneracies in the parameters encoded in the GW as well as probe the NS magnetic field strength, yielding insights into open problems in NS magnetic field decay.

  12. Radio Counterparts to SXR Transients

    NASA Astrophysics Data System (ADS)

    Gary, D. E.

    1999-12-01

    By now several studies have been done on small-scale brightenings seen at radio, UV, EUV, and soft X-ray wavelengths. These are to be reviewed by Kundu in these proceedings. In this talk we concentrate on the radio counterpart of a particular type of brightening---the soft X-ray transient brightenings of Shimizu. These brightenings are associated with active regions, and a study of radio counterparts by White et al. (1995) using Nobeyama data found an excellent correspondence between the 17 GHz and SXR brightenings, both spatially and temporally. However, this study found that both the SXR and microwave emissions could be satisfactorily explained as purely thermal emission, and a search of BATSE hard X-ray data showed no nonthermal counterpart. White et al. (1995) were forced to conclude that the events may be different from flares. A more sensitive search for nonthermal emission was needed, in particular using lower frequency microwaves where the influence of nonthermal electrons would be more easily detected. Gary, Hartl and Shimizu (1997) found 34 SXR transient brightenings over a 10-day period in May 1992, for which OVRO (1-18 GHz) total power data were available. A comparison of the data showed a number of clear nonthermal signatures. In addition, one of the events was seen in the lowest energy (6-9.3 keV) channel of the BATSE SPEC detector, suggesting a connection between the microflares discovered in hard X-rays by Lin et al. (1984). The evidence that SXR transient brightenings are microflares is reviewed in this talk. We also attempt to place other small-scale brightenings in context with regard to SXR transient brightenings and microflares.

  13. Coping with Radio Frequency Interference

    NASA Astrophysics Data System (ADS)

    Lewis, B. M.

    2009-01-01

    The radio spectrum is a finite resource, on which humanity makes many demands. And pressure on it is ever increasing with the development of new technology and ideas for radio services. After all, we all benefit from wifi and cell phones. Radio astronomers have a small percentage of the spectrum allocated to them at octave intervals in the metre-centimetre bands, and at important frequencies, such as that of the 21cm line of HI. Signals from other services, as well as from our own poorly-engineered equipment, sometimes contaminate our bands: these signals constitute RFI. These may totally obliterate the astronomical signal, or, in the case of CLOUDSAT, may be capable of completely destroying a receiver, which introduces us to the new possibility of 'destructive interference'. A geo-stationary satellite can block access to a piece of sky from one site. Good equipment design eliminates self-inflicted interference, while physical separation often provides adequate practical mitigation at many frequencies. However, new observatories end up being located in the West Australian desert or Antarctica. In future they may be on the back side of the Moon. But there is no Earth-bound protection via physical separation against satellite signals. Some mitigation can be achieved by frequent data dumps and the excision of RFI, or by real-time detection and blanking of the receiver, or by more sophisticated algoriths. Astronomers of necessity aim to achieve mitigation via coordination, at the local level, and by participating in spectrum management at the national and international levels. This involves them spending a lot of time in Geneva at the International Telegraphic Union protecting their access to spectrum, and access to clean spectrum from the L3 point and the far side of the Moon.

  14. Radio emission in peculiar galaxies

    NASA Technical Reports Server (NTRS)

    Demellorabaca, Dulia F.; Abraham, Zulema

    1990-01-01

    During the last decades a number of surveys of peculiar galaxies have been carried out and accurate positions become available. Since peculiarities are a possible evidence of radio emission (Wright, 1974; Sulentic, 1976; Stocke et al., 1978), the authors selected a sample of 24 peculiar galaxies with optical jet-like features or extensions in different optical catalogues, mainly the Catalogue of Southern Peculiar Galaxies and Associations (Arp and Madore, 1987) and the ESO/Uppsala Survey of the ESO(B) Atlas (Lauberts, 1982) for observation at the radio continuum frequency of 22 GHz. The sample is listed in a table. Sol (1987) studied this sample and concluded that the majority of the jet-like features seem to admit an explanation in terms of interactive galaxies with bridges and/or tails due to tidal effects. Only in a few cases do the jets seem to be possibly linked to some nuclear activity of the host galaxy. The observations were made with the 13.7m-radome enclosed Itapetinga Radiotelescope (HPBW of 4.3 arcmin), in Brazil. The receiver was a 1 GHz d.s.b. super-heterodine mixer operated in total-power mode, with a system temperature of approximately 800 K. The observational technique consisted in scans in right ascention, centralized in the optical position of the galaxy. The amplitude of one scan was 43 arcmin, and its duration time was 20 seconds. The integration time was at least 2 hours (12 ten-minute observations) and the sensibility limit adopted was an antenna temperature greater than 3 times the r.m.s. error of the baseline determination. Virgo A was used as the calibrator source. Three galaxies were detected for the first time as radio sources and four other known galaxies at low frequencies had their flux densities measured at 22 GHz. The results for these sources are presented.

  15. Low Radio Frequency Picosatellite Missions

    NASA Astrophysics Data System (ADS)

    Jones, Dayton L.

    2014-06-01

    The dramatic advances in cubesat and other picosatellite capabilities are opening the door for scientifically important observations at low radio frequencies. Because simple antennas are effective at low frequencies, and receiver technology allows low mass and low power instruments, these observations are an ideal match for very small spacecraft. A workshop on cubesat missions for low frequency radio astronomy was held at the Kiss Institute for Space Sciences, Caltech, to explore mission concepts involving one up to hundreds of picosatellites. One result from this workshop was that there are opportunities for viable missions throughout this large range. For example, the sky-integrated spectral signature of highly redshifted neutral hydrogen from the dark ages and cosmic dawn epochs can be measured by a single antenna on a single spacecraft. There are challenging issues of calibration, foreground removal, and RF interference that need to be solved, but the basic concept is appealingly simple. At the other extreme, imaging of angular structure in the high-redshift hydrogen signal will require an interferometer array with a very large number of antennas. In this case the primary requirement is a sufficiently low individual spacecraft mass that hundreds can be launched affordably. The technical challenges for large arrays are long-term relative station keeping and high downlink data rates. Missions using several to a few tens of picosatellites can image and track bright sources such as solar and planetary radio bursts, and will provide essential validation of technologies needed for much larger arrays.This work has been carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

  16. Evolution of radio galaxies to z = 1

    NASA Technical Reports Server (NTRS)

    Hutchings, J. B.; Neff, S. G.; Weadock, J.; Roberts, L.; Ryneveld, S.; Gower, A. C.

    1994-01-01

    We report Very Large Array (VLA) A-configuration studies of a sample of 49 radio galaxies at redshift less than 1. These were selected with no prior knowledge of their morphology and were chosen to match the redshift and luminosity distribution of a previously studied sample of radio-loud quasars. We compare the radio galaxies with the quasar sample and also with a sample of 29 radio galaxies selected for steep spectrum and double-lobe structure. We find that the radio galaxies have more luminous lobes and mostly weaker cores, and there is no population of one-sided sources associated with the galaxies. The radio galaxies' lobe length ratios and lobe power ratios differ from quasars. The overall sizes of the two types of sources are similar, but the radio galaxies have a 3 times larger upper envelope. The distribution of bend angles is similar but the radio galaxies have fewer very bent and straight sources. We discuss these and other comparisons in detail and suggest that while quasars appear to be viewed within a cone and radio galaxies outside it, the two types of source also have intrinsic differences, and both have individual growth and evolution scenarios. This is supported by previously observed differences in optical properties between the two source types.

  17. Radio Astronomy in Serbia: A Short Review

    NASA Astrophysics Data System (ADS)

    Urosevic, D.

    In this lecture, I presented a short review of: 1. the brief history of development of radio astronomy in Serbia, and 2. the present state of research and university teaching in Serbia on this interesting and modern field of astronomy. Since 1970's, the continuum observations at the lowest radio frequencies (e.g. 38 MHz) and the Galactic radio loops have been represented the topics of main research interest for the first radio astronomer in Serbia, prof. dr Jelena Milogradov-Turin. In 1983, she introduced Radio astronomy as two semester course at 4th year of studies at Department of astronomy, Faculty of Mathematics, University of Belgrade. In this moment we have radio astronomy group with 5 (mainly younger) researchers from Department of Astronomy and Belgrade Astronomical Observatory. The main fields of research interest are, as a part of tradition, the Galactic radio loops and additionally, the hydrodynamic and radio evolution of supernova remnants. Our future projects will be connected with radio evolution of nova remnants and planetary nebulae.

  18. Abell 1033: birth of a radio phoenix

    NASA Astrophysics Data System (ADS)

    de Gasperin, F.; Ogrean, G. A.; van Weeren, R. J.; Dawson, W. A.; Brüggen, M.; Bonafede, A.; Simionescu, A.

    2015-04-01

    Extended steep-spectrum radio emission in a galaxy cluster is usually associated with a recent merger. However, given the complex scenario of galaxy cluster mergers, many of the discovered sources hardly fit into the strict boundaries of a precise taxonomy. This is especially true for radio phoenixes that do not have very well defined observational criteria. Radio phoenixes are aged radio galaxy lobes whose emission is reactivated by compression or other mechanisms. Here, we present the detection of a radio phoenix close to the moment of its formation. The source is located in Abell 1033, a peculiar galaxy cluster which underwent a recent merger. To support our claim, we present unpublished Westerbork Synthesis Radio Telescope and Chandra observations together with archival data from the Very Large Array and the Sloan Digital Sky Survey. We discover the presence of two subclusters displaced along the N-S direction. The two subclusters probably underwent a recent merger which is the cause of a moderately perturbed X-ray brightness distribution. A steep-spectrum extended radio source very close to an active galactic nucleus (AGN) is proposed to be a newly born radio phoenix: the AGN lobes have been displaced/compressed by shocks formed during the merger event. This scenario explains the source location, morphology, spectral index, and brightness. Finally, we show evidence of a density discontinuity close to the radio phoenix and discuss the consequences of its presence.

  19. RX Puppis - Detection of asymmetrical radio structure

    NASA Technical Reports Server (NTRS)

    Hollis, J. M.; Yusef-Zadeh, F.; Oliversen, R. J.; Michalitsianos, A. G.; Cornwell, T. J.

    1989-01-01

    Subarcsecond observations of the RX Puppis symbiotic system with the VLA have resolved 2 cm continuum emission which deviates from a previously reported circularly symmetric radio distribution. The radio structure is comprised of at least three nearly colinear components. Under the assumption that the strongest feature is coincident with the hot star, the other two features lie 230 and 590 AU distant. These radio features are reminiscent of small-scale radio structure detected toward R Aquarii, another symbiotic star system, and probably represents material ejected from the RX Puppis system at an earlier epoch.

  20. Radio communications with extra-terrestrial civilizations

    NASA Technical Reports Server (NTRS)

    Kotelnikov, V. A.

    1974-01-01

    Communications between civilizations within our galaxy at the present level of radio engineering is possible, although civilizations must begin to search for each other to achieve this. If an extra-terrestrial civilization possessing a technology at our level wishes to make itself known and will transmit special radio signals to do this, then it can be picked up by us at a distance of several hundreds of light years using already existing radio telescopes and specially built radio receivers. If it wishes, this civilization can also send us information without awaiting our answer.

  1. Gamma-ray burster counterparts - Radio

    NASA Technical Reports Server (NTRS)

    Schaefer, Bradley E.; Cline, Thomas L.; Desai, U. D.; Teegarden, B. J.; Atteia, J.-L.; Barat, C.; Estulin, I. V.; Evans, W. D.; Fenimore, E. E.; Hurley, K.

    1989-01-01

    Many observers and theorists have suggested that gamma-ray bursters (GRBs) are related to highly magnetized rotating, neutron stars, in which case an analogy with pulsars implies that GRBs would be prodigious emitters of polarized radio emission during quiescence. The paper reports on a survey conducted with the Very Large Array radio telescope of 10 small GRB error regions for quiescent radio emission at wavelengths of 2, 6, and 20 cm. The sensitivity of the survey varied from 0.1 to 0.8 mJy. The observations did indeed reveal four radio sources inside the GRB error regions.

  2. Observing Solar and Jovian Radio Bursts

    NASA Astrophysics Data System (ADS)

    Grippaldi, Joseph

    2011-05-01

    A recently constructed low frequency radio telescope has been constructed on the campus of the The College of New Jersey (TCNJ) has recently begun conducting observations at 20MHz as part of NASA'a Radio Jove program. This instrument is capable of observations of Jovian radio emission including strong prompt radio emission associated with the Jovian moon Io. We will discuss Jovian observations conducted with this instrument as an effort to conduct coincident observation with the Eight-meter-wavelength Transient Array (ETA) and the Long Wavelength Array (LWA).

  3. ``Water Drops'' Essays Available for Public Radio

    NASA Astrophysics Data System (ADS)

    Black, Peter E.

    2007-11-01

    ``Water Drops'' are 90-second essays on water science, hydrology, culture, history, organizations, law, and policy that have aired weekly on radio station WRVO-FM in Oswego, N.Y., since January 2006. Created for the lay public with a basic understanding of Earth science, the 133 essays now are available on Public Radio Exchange (http://www.prx.org) for free use by public radio stations, according to terms set forth at the Exchange Web site that include citing appropriate credits. If aired weekly, there are enough essays for 2.5 years of radio programming.

  4. Millisecond radio pulsars in globular clusters

    NASA Technical Reports Server (NTRS)

    Verbunt, Frank; Lewin, Walter H. G.; Van Paradijs, Jan

    1989-01-01

    It is shown that the number of millisecond radio pulsars, in globular clusters, should be larger than 100, applying the standard scenario that all the pulsars descend from low-mass X-ray binaries. Moreover, most of the pulsars are located in a small number of clusters. The prediction that Teran 5 and Liller 1 contain at least about a dozen millisecond radio pulsars each is made. The observations of millisecond radio pulsars in globular clusters to date, in particular the discovery of two millisecond radio pulsars in 47 Tuc, are in agreement with the standard scenario, in which the neutron star is spun up during the mass transfer phase.

  5. Meteor trajectory estimation from radio meteor observations

    NASA Astrophysics Data System (ADS)

    Kákona, J.

    2016-01-01

    Radio meteor observation techniques are generally accepted as meteor counting methods useful mainly for meteor flux detection. Due to the technical progress in radio engineering and electronics a construction of a radio meteor detection network with software defined receivers has become possible. These receivers could be precisely time synchronized and could obtain data which provide us with more information than just the meteor count. We present a technique which is able to compute a meteor trajectory from the data recorded by multiple radio stations.

  6. Venus - Global surface radio emissivity

    NASA Technical Reports Server (NTRS)

    Ford, P. G.; Pettengill, G. H.

    1983-01-01

    Observations of thermal radio emission from the surface of Venus, made by the Pioneer Venus radar mapper at a wavelength of 17 cm, show variations that are dominated by changes in surface emissivity. The regions of lowest emissivity (0.54 + or - 0.05 for the highland areas of Aphrodite Terra and Theia Mons) correspond closely to regions of high radar reflectivity reported earlier. These results support the inference of inclusions of material with high electrical conductivity in the surface rock of these areas.

  7. The Bruny Island Radio Spectrometer

    NASA Astrophysics Data System (ADS)

    Erickson, W. C.

    1997-11-01

    A radio spectrometer has been built on Bruny Island, south of Hobart, for the study of solar bursts in the rarely observed frequency range from 3 to 20 MHz. This spectrometer is an adaptive device that employs digital techniques to avoid most of the strong terrestrial interference prevalent in this frequency range. The residual interference that cannot be avoided is excised during off-line processing. As a result, successful observations are made down to the minimum frequency that can propagate through the ionosphere to the antenna. This minimum frequency depends upon the zenith distance of the Sun and it is usually between 4 and 8 MHz.

  8. High Explosive Radio Telemetry System

    SciTech Connect

    Bracht, R.R.; Crawford, T.R.; Johnson, R.L.; Mclaughlin, B.M.

    1998-11-04

    This paper overviews the High Explosive Radio Telemetry (HERT) system, under co-development by Los Alamos National Laboratories and Allied Signal Federal Manufacturing & Technologies. This telemetry system is designed to measure the initial performance of an explosive package under flight environment conditions, transmitting data from up to 64 sensors. It features high speed, accurate time resolution (10 ns) and has the ability to complete transmission of data before the system is destroyed by the explosion. In order to affect the resources and performance of a flight delivery vehicle as little as possible, the system is designed such that physical size, power requirements, and antenna demands are as small as possible.

  9. Hybrid spread spectrum radio system

    DOEpatents

    Smith, Stephen F.; Dress, William B.

    2010-02-02

    Systems and methods are described for hybrid spread spectrum radio systems. A method includes modulating a signal by utilizing a subset of bits from a pseudo-random code generator to control an amplification circuit that provides a gain to the signal. Another method includes: modulating a signal by utilizing a subset of bits from a pseudo-random code generator to control a fast hopping frequency synthesizer; and fast frequency hopping the signal with the fast hopping frequency synthesizer, wherein multiple frequency hops occur within a single data-bit time.

  10. Genome Radio Project: Quarterly report

    SciTech Connect

    1997-08-01

    The process of conducting background research for the programs of the Genome Radio Project is continuing. The most developed of the program ``backgrounders`` have been reviewed by series and program advisors from various fields. Preliminary and background interviews have been conducted with dozens of potential program participants and advisors. Structurally, efforts are being directed toward developing and formalizing the project and series advisor relationships so that the best use can be made of those experts who have offered to assist the project in its presentation of program content. The library of research materials has been expanded considerably, creating a useful resource library for the producers.

  11. RADIO PROPERTIES OF LOW-REDSHIFT BROAD-LINE ACTIVE GALACTIC NUCLEI INCLUDING EXTENDED RADIO SOURCES

    SciTech Connect

    Rafter, Stephen E.; Crenshaw, D. Michael; Wiita, Paul J.

    2011-03-15

    We present a study of the extended radio emission in a sample of 8434 low-redshift (z < 0.35) broad-line active galactic nuclei (AGNs) from the Sloan Digital Sky Survey. To calculate the jet and lobe contributions to the total radio luminosity, we have taken the 846 radio core sources detected in our previous study of this sample and performed a systematic search in the FIRST database for extended radio emission that is likely associated with the optical counterparts. We found that 51 out of 846 radio core sources have extended emission (>4'' from the optical AGN) that is positively associated with the AGN, and we have identified an additional 12 AGNs with extended radio emission but no detectable radio core emission. Among these 63 AGNs, we found 6 giant radio galaxies, with projected emission exceeding 750 kpc in length, and several other AGNs with unusual radio morphologies also seen in higher redshift surveys. The optical spectra of many of the extended sources are similar to those of typical broad-line radio galaxy spectra, having broad H{alpha} emission lines with boxy profiles and large M{sub BH}. With extended emission taken into account, we find strong evidence for a bimodal distribution in the radio-loudness parameter R ({identical_to}{nu}{sub radio} L{sub radio}/{nu}{sub opt} L{sub opt}), where the lower radio luminosity core-only sources appear as a population separate from the extended sources, with a dividing line at log(R) {approx}1.75. This dividing line ensures that these are indeed the most radio-loud AGNs, which may have different or extreme physical conditions in their central engines when compared to the more numerous radio-quiet AGNs.

  12. A Profile of Independent Local Radio (Commercial Radio in Great Britain).

    ERIC Educational Resources Information Center

    Sidel, M. Kent

    Commercial and noncommercial radio in the United States and Great Britain have followed opposite paths of development. Unlike the United States, where commercial radio was the historical cornerstone of the broadcasting system, the Independent Local Radio (ILR) of Britain is the newcomer into an environment heavy with the heritage of the…

  13. Kothmale Community Radio Interorg Project: True Community Radio or Feel-Good Propaganda?

    ERIC Educational Resources Information Center

    Harvey-Carter, Liz

    2009-01-01

    The Kothmale Community Radio and Interorg project in Sri Lanka has been hailed as an example of how a community radio initiative should function in a developing nation. However, there is some question about whether the Kothmale Community Interorg Project is a true community radio initiative that empowers local communities to access ICT services…

  14. Spread spectrum mobile radio communications

    NASA Astrophysics Data System (ADS)

    Gupta, S. C.; Soliman, S. S.

    1987-02-01

    This report is made up of two parts. In the first part we present additional results on the performance of random access protocols for mobile packet radio networks. The effect of three different types of diversity reception in Nakagami fading environment on the channel throughput and the average packet delay of nonpersistent carrier sense multiple access (NPCSMA) protocol is considered. Expressions for the probability of packet error with diversity receptions are newly obtained for both independent and correlated diversity branches. A noncoherent frequency shift keying modulation scheme is assumed. In the second part a comprehensive study of the problem of synchronization over fading dispersive channels is presented. Synchronization is a fundamental problem in digital communications as used in mobile radio. In the first chapter, we consider a simple binary detection problem. The effect of receiver mismatch is investigated. A closed form expression for the probability of false alarm and probability of detection are given, also a set of curves are provided to demonstrate the amount of degradation for under-spread channels with some special scattering.

  15. Layered sensing with radio (LSWR)

    NASA Astrophysics Data System (ADS)

    Mitra, Atindra K.

    2010-04-01

    An alternative approach to a Layered Sensing System-of-Systems methodology, denoted as LSWR (Layered Sensing With Radio), is outlined in this paper. This is a novel Broadcast-TV-Driven layered sensing technique that shows potential for finding embedded objects within, for example, buildings via leveraging and combining existing commercial satellite technologies with COTS (Commercial Off-the-Shelf) wireless network technologies and state-of-the-art wireless sensor mote technologies. Specifically, compact sensor mote technologies are employed in a cost-effective manner to interface with and control low-cost satellite radio/broadcast tuners. With this approach, initial concepts of this type are investigated via the analysis of compact custom sensor node technology (i.e. wireless sensor mote interfaced with satellite broadcast tuner) integrated onto a UGV (unmanned ground vehicle) robot arm for purposes developing prototype UGV robot systems with passive integrated RF sensors that support, for example, networked thru-wall embedded object detection. The primary category of commercial satellite signal considered for analysis within this paper is known as DVB (Digital Video Broadcast).

  16. The life cycle of radio galaxies

    NASA Astrophysics Data System (ADS)

    Young, Andrew

    2004-06-01

    This thesis will examine some key issues in the life history of radio galaxies. The evolution of radio galaxies can be understood in terms of the history of their relativistic particle distributions and morphologies. Using radio data from the Very Large Array, I examine the relativistic particle acceleration processes in several Fanaroff-Riley I sources. 1116+28, 1243+26, and 1553+24 all show dual spectral components known as jets and sheaths. These and other radio galaxies show that the strength of the acceleration mechanism approaches the strong shock limit for first order Fermi acceleration. Active radio galaxies accelerate electrons that then undergo energy losses by way of synchrotron, adiabatic, and inverse-Compton mechanisms. 3C386 and 3C98 has structure which may indicate that the acceleration process has recently ceased or is coming to an end. An examination of these possibly dying radio sources with large, bright, and diffuse lobes reveals that the shape of the spectra indicates that their acceleration mechanisms approach the strong shock limit. With these derived low frequency spectral indices, an estimate of the true magnetic field strength in the lobes can be made should X-ray observations be available. This will alleviate the need to invoke equipartition assumptions. A radio galaxy will eventually lose almost all of its relativistic electron energy through radiative and adiabatic losses and evolve into a relic state. In this state, there may have no discernible radio core, radio jet, or optical counterpart. However, mechanisms such as cluster merger shocks or re-started radio galaxies could re-energize these relic plasmas. Relic radio sources in the clusters Abell 85 and MKW 3s show that these processes do occur and reveal spectra that are consistent with weak shocks. The sources studied here can be viewed as a snapshot in the timeline of a radio galaxy. The life cycles of radio galaxies have broad implications not just for themselves but also on the

  17. A Radio Astronomy Curriculum for STARLAB

    NASA Astrophysics Data System (ADS)

    Boltuch, D.; Hund, L.; Buck, S.; Fultz, C.; Smith, T.; Harris, R.; Castelaz, M. W.; Moffett, D.; LaFratta, M.; Walsh, L.

    2005-12-01

    We present elements of a curriculum that will accompany the STARLAB module "Sensing the Radio Sky" a portable planetarium program and projection of the radio sky. The curriculum will serve to familiarize high school students to a set of topics in radio astronomy. The curriculum includes lessons and activities addressing several topics related to radio astronomy and the Milky Way that consists of two main resources: a manual and a multimedia website. It is designed to accommodate a wide variety of possible uses and time constraints. The manufacturer of STARLAB, Learning Technologies, Inc. produces a short manual to accompany each presentation for the STARLAB. The "Sensing the Radio Sky" manual we have created includes the mandatory, minimum background information that students need to understand radio astronomy. It briefly discusses waves and electromagnetic radiation, similarities and differences between optical and radio astronomy, probable misconceptions about radio astronomy, how radio images are produced, synchrotron radiation in the Milky Way, and galactic coordinates. It also includes a script that presenters can choose to follow inside the STARLAB, a lesson plan for teachers, and activities for students to complete before and after the STARLAB experience that mirror the scientific method. The multimedia website includes more detailed information about electromagnetic radiation and a more detailed comparison of optical and radio astronomy. It also discusses the life cycles of stars, radiation from a variety of specific sources, and pulsars, as each relates to radio astronomy. The five highly detailed lessons are pulled together in sixth "overview lesson", intended for use by teachers who want to present more than the basic material in the manual, but do not have the classroom time to teach all five of the in-depth lessons. . We acknowledge support from the NSF Internship in Public Science Education Program grant number 0324729.

  18. Radio Continuum and Radio Recombination Line Observations of W51

    NASA Astrophysics Data System (ADS)

    Mehringer, David M.

    1995-04-01

    Radio continuum observations at 3.6, 6, and 20 cm of W51 A (G49.5--0.4) have been carried out using the VLA in the C and D configurations. The maximum resolution is 3". The goals of this study were to determine the spectra of the individual components and to derive the physical parameters of the gas, such as the electron number density and emission measure. A number of other sources in the W51 complex, including G49.4--0.3, were included in the 20 cm primary beam. Several new H II regions were detected. An H92-alpha (8.3 GHz) radio recombination line (RRL) observation was also carried out using the C configuration of the VLA with an angular resolution of 3". The goals of the RRL observation were to determine the kinematics and the electron temperature of the ionized gas as well as the abundance of singly ionized helium relative to ionized hydrogen. The results of this study indicate that most of the ionized gas in G49.5--0.4 has velocities in the range 40 to 80 km/s. However, there is some gas in a compact region (source d(1)) at a velocity of --41 km/s. If this region is in circular rotation about the Galactic center, it is located 15 kpc from the sun. Another possibility is that d(1) is a shell-like structure that is being viewed edge on and the near side is expanding toward the observer at 80 km/s. Derived LTE electron temperatures are in the range of 4500 to 11,000 K with a mean of 7800 +/- 1200 K. The ionized helium abundance is 0.096 +/- 0.015.

  19. 46 CFR 169.715 - Radio.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Radio. 169.715 Section 169.715 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Vessel Control, Miscellaneous Systems, and Equipment § 169.715 Radio. (a) Radiotelegraph and radiotelephone installations...

  20. 46 CFR 169.715 - Radio.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Radio. 169.715 Section 169.715 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Vessel Control, Miscellaneous Systems, and Equipment § 169.715 Radio. (a) Radiotelegraph and radiotelephone installations...

  1. Youth Radio and the Pedagogy of Collegiality

    ERIC Educational Resources Information Center

    Chavez, Vivian; Soep, Elisabeth

    2005-01-01

    In this article, Vivian Chavez and Elisabeth Soep explore the collaboration among youth and adult participants at Youth Radio, a broadcast-training program in the San Francisco Bay Area. At Youth Radio, participants transcend the conventional relationship between adult "teachers" and youth "learners" to coproduce media products. Chavez and Soep…

  2. Radio's Changing Environment. Info. Packets No. 22.

    ERIC Educational Resources Information Center

    Bailey, George

    The purpose of this report is to identify changes in the radio environment, especially those which affect public radio's ability to compete. In Boston and other markets around the country, most formats have subdivided into targeted niches. The effect has been to even out station shares, so that rather than trying to reach mass audiences,…

  3. Listening to Monotony: All-News Radio.

    ERIC Educational Resources Information Center

    Woal, Michael

    A study analyzed statistically the monotony of all-news radio listening and identified stylistic figures that elicit attention in listeners. Subjects were 30 graduate students whose experience with radio news ranged from occasional listening over several months to regular listening five or seven days per week for several years. Respondents were…

  4. Radio Map of the Andromeda Galaxy.

    PubMed

    Macleod, J M

    1964-07-24

    The University of Illinois radio telescope has resolved the 610.5 Mcy/sec disk component of radio emission from the large galaxy M 31 into several discrete concentrations. In two cases, these correspond to the crossing of the optical major axis by spiral arms. A spur of emission extends southeast from the galaxy near the minor axis. PMID:17816977

  5. Radio and Television Servicing. Intermediate Course.

    ERIC Educational Resources Information Center

    Campbell, Guy; And Others

    Several intermediate performance objectives and corresponding criterion measures are listed for each of 32 terminal objectives for an intermediate (second year) radio/TV servicing course. This 1-year course (3 hours daily) was designed to provide the student with the basic skills and knowledges necessary for entry level employment in the Radio/TV…

  6. Radio Communication Systems for the Disabled

    ERIC Educational Resources Information Center

    Kent, Herbert; Lesieur, Russel C.

    1978-01-01

    Presented are pertinent essentials concerning the use of Citizens Radio Service, particularly class D, and the Amateur Radio Service for the physically disabled. Prohibited and permitted uses are described in detail, and the Ten Code and some fundamental concepts are discussed. Eligibility and filing directions are also included. (BM)

  7. Hospital radio: advertisements get an airing.

    PubMed

    1980-08-15

    As a DHSS circular opens the door to advertising on hospital radio, someone who describes himself mysteriously as a "senior health service administrator in North London with a special interest in radio communication and allied subjects' reports how one station has risen to the challenge. PMID:10248328

  8. Health Education by Radio: A Zambian Experience.

    ERIC Educational Resources Information Center

    Chitanda, Rackson

    Zambia's Health Education News radio program, which was launched in 1982, features 15-minute broadcasts in English and several local languages. The primary objectives of the radio program are to encourage individuals to attend various health clinics and get their children immunized, teach communities to value their health, make people accept…

  9. A Radio-Controlled Car Challenge

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2010-01-01

    Watching a radio-controlled car zip along a sidewalk or street has become a common sight. Within this toy are the basic ingredients of a mobile robot, used by industry for a variety of important and potentially dangerous tasks. In this challenge, students consider modifying an of-the-shelf, radio-controlled car, adapting it for a robotic task.

  10. The RadioSat (sm) network

    NASA Technical Reports Server (NTRS)

    Noreen, Gary K.

    1991-01-01

    The RadioSat network under development by radio Satellite Corporation will use mobile satellite (MSAT) technology to provide diverse personal communications, broadcast, and navigation services. The network will support these services simultaneously for integrated mobile radios throughout Canada and the United States. The RadioSat network takes advantage of several technological breakthroughs, all coming to fruition by the time the first MSAT satellite is launched in 1994. The most important of these breakthroughs is the enormous radiated power of each MSAT spacecraft - orders of magnitude greater than the radiated power of previous L-band spacecraft. Another important breakthrough is the development of advanced digital audio compression algorithms, enabling the transmission of broadcast quality music at moderate data rates. Finally, continuing dramatic increases in VLSI capabilities permit the production of complex, multi-function mobile satellite radios in very large quantities at prices little more than those of conventional car radios. In addition to performance breakthroughs and their economic implications to RadioSat, the design of the RadioSat network is reviewed.

  11. Rural Radio in Dahomey: September, 1972.

    ERIC Educational Resources Information Center

    McAnany, Emile G.

    Rural Radio (RR) in Dahomey has a radio network that covers most of the national territory with two transmitters plus 4KW short wave. The program themes are suggested by an advisory group from interested ministries such as Education, Youth and Sport, Agriculture, Health, etc., but the primary objective of the project lies in promoting dialogues…

  12. Nonthermal processing by radio frequency electric fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Radio frequency electric fields (RFEF) processing is relatively new and has been shown to inactivate bacteria in apple juice, orange juice and apple cider at moderately low temperatures. Key equipment components of the process include a radio frequency power supply and a treatment chamber that is ca...

  13. 50 CFR 300.37 - Radio monitoring.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 11 2014-10-01 2014-10-01 false Radio monitoring. 300.37 Section 300.37 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS South Pacific Tuna Fisheries § 300.37 Radio monitoring. The international distress frequency, 2.182...

  14. 50 CFR 300.37 - Radio monitoring.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Radio monitoring. 300.37 Section 300.37 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS South Pacific Tuna Fisheries § 300.37 Radio monitoring. The international distress frequency, 2.182...

  15. 50 CFR 300.37 - Radio monitoring.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 11 2012-10-01 2012-10-01 false Radio monitoring. 300.37 Section 300.37 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS South Pacific Tuna Fisheries § 300.37 Radio monitoring. The international distress frequency, 2.182...

  16. 50 CFR 300.37 - Radio monitoring.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Radio monitoring. 300.37 Section 300.37 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS South Pacific Tuna Fisheries § 300.37 Radio monitoring. The international distress frequency, 2.182...

  17. 50 CFR 300.37 - Radio monitoring.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 11 2013-10-01 2013-10-01 false Radio monitoring. 300.37 Section 300.37 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS South Pacific Tuna Fisheries § 300.37 Radio monitoring. The international distress frequency, 2.182...

  18. Space Telecommunications Radio Architecture (STRS): Technical Overview

    NASA Technical Reports Server (NTRS)

    Reinhart, Richard C.

    2006-01-01

    A software defined radio (SDR) architecture used in space-based platforms proposes to standardize certain aspects of radio development such as interface definitions, functional control and execution, and application software and firmware development. NASA has charted a team to develop an open software defined radio hardware and software architecture to support NASA missions and determine the viability of an Agency-wide Standard. A draft concept of the proposed standard has been released and discussed among organizations in the SDR community. Appropriate leveraging of the JTRS SCA, OMG s SWRadio Architecture and other aspects are considered. A standard radio architecture offers potential value by employing common waveform software instantiation, operation, testing and software maintenance. While software defined radios offer greater flexibility, they also poses challenges to the radio development for the space environment in terms of size, mass and power consumption and available technology. An SDR architecture for space must recognize and address the constraints of space flight hardware, and systems along with flight heritage and culture. NASA is actively participating in the development of technology and standards related to software defined radios. As NASA considers a standard radio architecture for space communications, input and coordination from government agencies, the industry, academia, and standards bodies is key to a successful architecture. The unique aspects of space require thorough investigation of relevant terrestrial technologies properly adapted to space. The talk will describe NASA's current effort to investigate SDR applications to space missions and a brief overview of a candidate architecture under consideration for space based platforms.

  19. The Fascinating World of Radio Communications.

    ERIC Educational Resources Information Center

    Green, Wayne, Ed.

    Intended mainly for the amateur radio operator, or "ham," this book outlines some of the pleasures to be had in amateur radio, including DXing (calling distant stations) and helping in emergencies. The steps in starting out on this hobby, including getting Citizens' Band (CB) gear, a CB license, and a receiver and antenna, are described. Also…

  20. Principles of Radio: A Laboratory Experiment

    ERIC Educational Resources Information Center

    Kraftmakher, Yaakov

    2002-01-01

    An experiment is proposed for learning the principles of radio. A simple radio receiver illustrates amplitude modulation and demodulation, the selectivity of a receiver and the features of a directional antenna. Both normal and computerized versions of the experiment are described. The computerized experiment employs the "ScienceWorkshop"…

  1. Antenna Construction and Propagation of Radio Waves.

    ERIC Educational Resources Information Center

    Marine Corps Inst., Washington, DC.

    Developed as part of the Marine Corps Institute (MCI) correspondence training program, this course on antenna construction and propagation of radio waves is designed to provide communicators with instructions in the selection and/or construction of the proper antenna(s) for use with current field radio equipment. Introductory materials include…

  2. Regulation of Wire and Radio Communication.

    ERIC Educational Resources Information Center

    Federal Communications Commission, Washington, DC.

    This bulletin reviews early federal regulation of telegraphy, telephone, and radio communications, and the development of the Radio Acts of 1912 and 1927, the Communications Act of 1934, and the Communications Satellite Act of 1962. A large portion of the discussion focuses on the regulatory power and procedures of the Federal Communications…

  3. THE RADIO PROPERTIES OF TYPE 2 QUASARS

    SciTech Connect

    Lal, Dharam Vir; Ho, Luis C.

    2010-03-15

    This paper presents the first high-resolution and high-sensitivity study of the radio properties of optically selected type 2 quasars. We used the Very Large Array at 8.4 GHz to observe 59 sources drawn from the Sloan Digital Sky Survey sample of Zakamska et al.. The detection rate of our survey is 59% (35/59), comparable to the detection rate in FIRST at 1.4 GHz. Ongoing star formation, although present, contributes negligible radio emission at the current sensitivity limit. Comparing the radio powers with the [O III] {lambda}5007 luminosities, we find that roughly 15% {+-} 5% of the sample can be considered radio loud. Intriguingly, the vast majority of the detected sources in our sample fall in a region intermediate between those traditionally occupied by radio loud and radio quiet quasars. Moreover, most of these 'radio intermediate' sources tend to have flat or inverted radio spectra, which we speculate may be caused by free-free absorption by ionized gas in the narrow-line region. The incidence of flat-spectrum sources in type 2 quasars appears to be much higher than in type 1 quasars, in apparent violation of the simple orientation-based unified model for active galaxies.

  4. Transient pulsed radio emission from a magnetar.

    PubMed

    Camilo, Fernando; Ransom, Scott M; Halpern, Jules P; Reynolds, John; Helfand, David J; Zimmerman, Neil; Sarkissian, John

    2006-08-24

    Anomalous X-ray pulsars (AXPs) are slowly rotating neutron stars with very bright and highly variable X-ray emission that are believed to be powered by ultra-strong magnetic fields of >10(14) G, according to the 'magnetar' model. The radio pulsations that have been observed from more than 1,700 neutron stars with weaker magnetic fields have never been detected from any of the dozen known magnetars. The X-ray pulsar XTE J1810-197 was revealed (in 2003) as the first AXP with transient emission when its luminosity increased 100-fold from the quiescent level; a coincident radio source of unknown origin was detected one year later. Here we show that XTE J1810-197 emits bright, narrow, highly linearly polarized radio pulses, observed at every rotation, thereby establishing that magnetars can be radio pulsars. There is no evidence of radio emission before the 2003 X-ray outburst (unlike ordinary pulsars, which emit radio pulses all the time), and the flux varies from day to day. The flux at all radio frequencies is approximately equal--and at >20 GHz XTE J1810-197 is currently the brightest neutron star known. These observations link magnetars to ordinary radio pulsars, rule out alternative accretion models for AXPs, and provide a new window into the coronae of magnetars. PMID:16929292

  5. Need a Classroom Stimulus? Introduce Radio Astronomy

    ERIC Educational Resources Information Center

    Derman, Samuel

    2010-01-01

    Silently, invisibly, ceaselessly, our planet Earth is showered by radio waves from every direction and from every region of space. This radio energy originates in our solar system, throughout the Milky Way galaxy, and far beyond, out to the remotest reaches of the universe. Detecting and unraveling the origins of these invisible signals is what…

  6. Radio Clubs of Niger: September, 1972.

    ERIC Educational Resources Information Center

    McAnany, Emile G.

    The Radio Club Association of Niger (ARCN) is a private agency and has been in operation for ten years under the guidance of the radio section of the Ministry of Information. The primary objective of this project is not the assimilation of information but the growth in awareness of their situation by local people. Most of the program therefore…

  7. The Radio Sky in the STARLAB

    NASA Astrophysics Data System (ADS)

    Fultz, C.; Smith, T.; Buck, S.; Harris, R.; Boltuch, D.; Hund, L.; Moffett, D.; Walsh, L.; LaFratta, M.; Castelaz, M. W.

    2005-12-01

    The STARLAB is a portable planetarium created, produced, and distributed by Learning Technologies, Ltd. Upon entering the STARLAB, images are projected onto the ceiling of the planetarium's dome using custom, interchangeable projection cylinders mounted on top of an ultrabright point light source. The STARLAB is ideal for teaching students about astronomy since it may be easily transported to schools across the nation. In order to take advantage of this powerful teaching tool, one of the foremost priorities of the Sensing the Radio Sky project was the development a projection cylinder that would visually interpret the quantitative data taken with radio telescopes and present that information in a form that students could understand and appreciate. The final version of the cylinder demonstrates a variety of topics relevant to an understanding of radio astronomy. When using the Radio Sky cylinder in the STARLAB, teachers may discuss the differences between optical and radio astronomy such as the structure of the Milky Way Galaxy, different sources of electromagnetic radiation, and important radio sources within and outside of the Galaxy. In addition, the flexibility of the cylinder's design allows for a variety of educational activities to be conducted within the STARLAB, all complemented by the Radio Sky cylinder's unique presentation of the Galaxy in radio wavelengths. We acknowledge support from the NSF Internship in Public Science Education Program grant number 0324729.

  8. 47 CFR 80.1075 - Radio records.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Radio records. 80.1075 Section 80.1075 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Global Maritime Distress and Safety System (GMDSS) General Provisions § 80.1075...

  9. 47 CFR 80.1075 - Radio records.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Radio records. 80.1075 Section 80.1075 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Global Maritime Distress and Safety System (GMDSS) General Provisions § 80.1075...

  10. Evaluating Large-Scale Interactive Radio Programmes

    ERIC Educational Resources Information Center

    Potter, Charles; Naidoo, Gordon

    2009-01-01

    This article focuses on the challenges involved in conducting evaluations of interactive radio programmes in South Africa with large numbers of schools, teachers, and learners. It focuses on the role such large-scale evaluation has played during the South African radio learning programme's development stage, as well as during its subsequent…

  11. 47 CFR 80.1075 - Radio records.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Radio records. 80.1075 Section 80.1075 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Global Maritime Distress and Safety System (GMDSS) General Provisions § 80.1075...

  12. 47 CFR 80.1075 - Radio records.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Radio records. 80.1075 Section 80.1075 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Global Maritime Distress and Safety System (GMDSS) General Provisions § 80.1075...

  13. 47 CFR 80.1075 - Radio records.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Radio records. 80.1075 Section 80.1075 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Global Maritime Distress and Safety System (GMDSS) General Provisions § 80.1075...

  14. A Voyage through the Radio Universe

    ERIC Educational Resources Information Center

    Spuck, Timothy

    2004-01-01

    Each year, professionals and amateurs alike make significant contributions to the field of astronomy. High school students can also conduct astronomy research. Since 1992, the Radio Astronomy Research Team from Oil City Area Senior High School (OCHS) in Oil City, Pennsylvania, has traveled each year to the National Radio Astronomy Observatory…

  15. Proposed Integrated Radio-Telescope Network

    NASA Technical Reports Server (NTRS)

    Cohen, M. H.; Ewing, M. S.; Levy, G. S.; Mallis, R. K.; Readhead, A. C. S.; Smith, J. R.; Backer, D. C.

    1982-01-01

    Proposed network of radio telescopes, controlled by a central computer and managed by a single organization, offer potential for research on a scale that could not be matched by present privately and publicly-owned radio telescopes. With 10 antenna sites, network would establish base lines thousands of miles long. Antennas will be linked to computer center by telephone circuits.

  16. A Teaching Lab in Radio Astronomy

    ERIC Educational Resources Information Center

    Smith, Kirk R.; Cudaback, David D.

    1976-01-01

    Describes a study in which participants in a summer institute for secondary science teachers performed a series of experiments with a radio telescope. Concludes that a radio astronomy teaching facility would encourage students to use their own initiative and strategy in working with the scientific concepts involved. (MLH)

  17. The Radio Jove Project: Citizen Science Contributes to Jupiter Decametric Radio Research

    NASA Astrophysics Data System (ADS)

    Thieman, J.; Higgins, C. A.; Sky, J.; Cecconi, B.; Garcia, L. N.

    2014-12-01

    The Radio Jove Project is a hands-on educational activity in which students, teachers, and the general public build a simple radio telescope, usually from a kit, to observe single frequency decameter wavelength radio emissions from Jupiter, the Sun, the galaxy, and the Earth. Regular monitoring of Jupiter and solar radio storms is typical, and Radio Jove amateur observations have improved in their scientific utility. Some observers have upgraded their equipment to make spectroscopic observations in the frequency band from 15-30 MHz. These observations can be particularly useful when made in conjunction with professional telescopes such as the Long Wavelength Array (LWA), the Nancay Decametric Array, the Ukrainian UTR-2 Radio Telescope, etc. The coming Juno mission to Jupiter will observe the radio emissions while in orbit at Jupiter and will benefit from the Earth-based perspective provided by frequent monitoring of the emissions. With these goals in mind work is now underway to provide simple methods of archiving the Radio Jove observations for use by the amateur and professional radio science community in scientifically useful and easily analyzed formats. The data will be ingested to both Radio Jove specific databases and to archives containing a variety of "waves" data. Methods are being developed to assure the scientific validity of contributed data such as certification of the observers. Amateur scientists have made overwhelming contributions to optical astronomy and we believe the same is possible within the radio astronomy community as well.

  18. Software defined radio based multi-carrier multi-function waveform for cognitive radio

    NASA Astrophysics Data System (ADS)

    Zhou, Ruolin; Li, Xue; Chakravarthy, Vasu; Wu, Zhiqiang

    2010-04-01

    In this paper, we demonstrate an adaptive multicarrier multi-function waveform generator for cognitive radio via software defined radio. Using a USRP (universal software radio peripheral) software defined radio boards and GNU radio software, we implement a multi-carrier waveform generator which can generate multi-function waveforms such as OFDM, NC-OFDM, MC-CDMA, NC-MC-CDMA, CI/MC-CDMA, NCCI/ MC-CDMA, TDCS for cognitive radio. Additionally, we demonstrate a portable overlay cognitive radio using this multicarrier multi-function waveform generator. This cognitive radio is capable of detecting primary users in real time and adaptively adjusting its transmission parameters to avoid interference to primary users. More importantly, this cognitive radio can take advantage of multiple spectrum holes by employing non-contiguous multi-carrier transmission technologies. Additionally, we demonstrate that when the primary user transmission changes, the cognitive radio dynamically adjusts its transmission accordingly. We also demonstrate seamless real time video transmission between two cognitive radio nodes, while avoiding interference from primary users and interference to primary users operating in the same spectrum.

  19. Radio emissions from RHESSI TGFs

    NASA Astrophysics Data System (ADS)

    Mezentsev, Andrey; Østgaard, Nikolai; Gjesteland, Thomas; Albrechtsen, Kjetil; Cummer, Steven

    2016-04-01

    The discovery of bursts of energetic photons coming out to space from the Earth's atmosphere, referred to as terrsetrial gamma-ray flashes (TGFs), has stimulated research activity investigating different aspects of the TGF generation and accompanying processes. Two models of the TGF production are nowadays competing to explain the observations of the TGFs and related phenomena. One of the models involves the feedback mechanism enhancing the production rate of the runaway electrons in the ambient electric field of a thundercloud. Another model considers runaway electrons accelerated in the strong local electric field in front of the upward propagating negative leader of the +IC. We performed a detailed analysis of RHESSI TGFs detected between August 2004 and September 2015. It was reported that the RHESSI satellite clock has a systematic error of ˜ 1.8 ms, but the exact value remained unknown, also it was unclear if this systematic clock error is changing with time or not. We compared RHESSI TGFs with the world wide lightning location network (WWLLN) database and found the distribution of the time delays between the TGF peak times and associated WWLLN detections. This distribution allowed us to find the value of the RHESSI systematic clock offset with the microsecond accuracy level. Also we found that this offset experienced two changes: in August 2005 and in October 2013, which was confirmed by two independent ways. We found that in case of double TGFs WWLLN detection corresponds to the second TGF of the pair. VLF magnetic field recordings from the Duke University also attribute radio sferics to the second TGF, exhibiting no detectable radio emission during the first TGFs of the TGF pairs. We have proposed a possible scenario that is consistent with the observations. This scenario supports the leader-based model of the TGF generation. Spectral characteristics of 77 sferics recorded by the Duke University VLF sensors and related to the RHEESI TGFs show that maximal

  20. Radio wavelength transients: Current and emerging prospects

    NASA Astrophysics Data System (ADS)

    Lazio, J.

    2008-03-01

    Known classes of radio wavelength transients range from the nearby stellar flares and radio pulsars to the distant Universe γ-ray burst afterglows. Hypothesized classes of radio transients include analogs of known objects, e.g., extrasolar planets emitting Jovian-like radio bursts and giant-pulse emitting pulsars in other galaxies, to the exotic, prompt emission from γ-ray bursts, evaporating black holes, and transmitters from other civilizations. A number of instruments and facilities are either under construction or in early observational stages and are slated to become available in the next few years. With a combination of wide fields of view and wavelength agility, the detection and study of radio transients will improve immensely.

  1. The Different Wavelengths of Radio Science

    NASA Technical Reports Server (NTRS)

    Malecha, Jessica L.

    2005-01-01

    Radio Science covers many different avenues. This summer I attempted to work in each of the different avenues to learn the full range of subjects covered by Radio Science. I began my summer by traveling to Greece for the 3rd International Planetary Probe Workshop (IPPW-3). I went as a co-author of the Doppler Wind Experiment (DWE) team paper. My first job when I returned from Greece was to update the Radio Science activities webpage. I then used Fast Fourier Transforms (FFT) to find radio signals in recorded Radio Science experimental data and determine frequencies and powers. I read about and ran Fortran code being used to determine wind measurements on Huygens. I formatted and revised the abstracts and data lengths for the DVD data sets. By performing these tasks, I also learned the Unix operating system as well as a small amount of shell programming.

  2. UHF Radio Wave Attenuation Factor Database

    NASA Astrophysics Data System (ADS)

    Khomenko, S. I.; Kostina, V. L.; Mytsenko, I. M.; Roenko, A. N.

    2007-07-01

    As is known each sea-going vessel is equipped with navigation, communication and other radio engineering facilities that serve to secure the safety of navigation and are chiefly operated at UHF-wave band. In developing these systems and calculating the energy potential for a necessary coverage range one should be well aware of the radio signal attenuation processes on a propagation path. The key parameter of this path is the (radio) wave attenuation factor V and its distance dependence V(R). A diversity of factors influencing the radio signal attenuation over the oceanic expanses, especially well pronounced and quite stable tropospheric ducts, and the lack of experimental data were the compelling reasons why the researchers of the Institute for Radiophysics and Electronics, NASU, had spent many years on comprehensive radiophysical investigations carried out in different regions of the Atlantic, Indian, Arctic and Pacific Oceans. The experimental data obtained allow creating the database of radio wave attenuation factor V.

  3. Radio-Frequency Electronics, Circuits and Applications

    NASA Astrophysics Data System (ADS)

    Hagen, Jon B.

    This accessible and comprehensive book provides an introduction to the basic concepts and key circuits of radio frequency systems, covering fundamental principles which apply to all radio devices, from wireless data transceivers on semiconductor chips to high-power broadcast transmitters. Topics covered include filters, amplifiers, oscillators, modulators, low-noise amplifiers, phase-locked loops, and transformers. Applications of radio frequency systems are described in such areas as communications, radio and television broadcasting, radar, and radio astronomy. The book contains many exercises, and assumes only a knowledge of elementary electronics and circuit analysis. It will be an ideal textbook for advanced undergraduate and graduate courses in electrical engineering, as well as an invaluable reference for researchers and professional engineers in this area, or for those moving into the field of wireless communications.

  4. Early Radio Astronomy in the USSR

    NASA Astrophysics Data System (ADS)

    Kellermann, Kenneth I.

    2007-12-01

    As in many other countries, radio astronomy in the Soviet Union began as an outgrowth of wartime radar research. The early leaders of Soviet radio astronomy, including Simon Braude, Vladimir Kotelnikov, Vladimir Troitskii, and Viktor Vitkevitch, all began their careers during WWII. Although the theoretical contributions of people like Iosef Shklovsky and Vitaly Ginzburg were well known in the West, the early experimental and observational programs received much less attention, partially the result of cold war military secrecy. When they were noticed, the Soviet observations were largely ignored or declared wrong. We will discuss the controversial Soviet contributions to the detection of polarized cosmic radio emission, the development of very long baseline interferometry, the prediction and verification of radio recombination lines, and the first detection of variability in an extragalactic radio source.

  5. Modeling of radio emissions from Neptune

    NASA Astrophysics Data System (ADS)

    Menietti, J. D.; Curran, D. B.

    We have developed a plasma model of the Neptunian magnetosphere that includes a density cavity centered on the L=6 magnetic field line. Assuming the O8 magnetic field model, we have performed ray tracing of smooth radio emission from Neptune, and the results generally support the findings of Ladreiter et al. (1991), but differ in details of the source locations. In addition, we have examined source locations of bursty radio emission that are consistent with propagation at small wave normal angles as hypothesized for the temperature anisotropic beam instability (TABI) (Winglee et al., 1992). The source locations are adjacent (complementary) to the sources of the smooth radio emission. Using previously developed plasma and magnetic field models for Uranus, we have performed a similar study of bursty radio emissions. Again the source locations appear to be adjacent to the source regions of smooth radio emission, consistent with the TABI.

  6. Gamma-ray detected radio galaxies

    NASA Astrophysics Data System (ADS)

    Beckmann, Volker; Soldi, Simona; De Jong, Sandra; Kretschmer, Karsten; Savchenko, Volodymyr

    2016-07-01

    So far 15 radio galaxies have been detected in the gamma-ray domain by CGRO/EGRET and Fermi/LAT, with a few detections also in the VHE range. We search for distinguishing parameters and estimate the total number of gamma-ray emitting radio galaxies that are potentially detectable by Fermi/LAT. We use Fermi/LAT data in comparison with X-ray and hard X-ray data in order to constrain basic parameters such as the total power of the inverse Compton branch and the position of its peak. We search for possible correlations between the radio, UV, X-ray, and gamma-ray domain and derive the number counts distribution. We then compare their properties with those of the radio galaxies in the 3CRR and SMS4 catalogues. The data show no correlation between the peak of the inverse Compton emission and its luminosity. For the gamma-ray detected radio galaxies the luminosities in the various bands are correlated, except for the UV band, but there is no indication of a correlation of peak frequency or luminosity with the spectral slopes in the X-ray or gamma-ray band. The comparison with other bright radio galaxies shows that the gamma-ray detected objects are among those that have the largest X-ray but rather moderate radio fluxes. Their UV and X-ray luminosities are similar, but gamma-ray detected radio galaxies are predominantly of type FR-I, while the 3CRR sample contains mainly FR-II objects. The number counts of the so far gamma-ray detected radio galaxies shows a very shallow slope, indicating that potentially a fraction of radio galaxies has been missed so far or has not been identified as such, although the predicted number of 22 ± 7 is consistent with the observed 15 objects.

  7. Radio Monitoring of Protoplanetary Discs

    NASA Astrophysics Data System (ADS)

    Ubach, Catarina; Tahli Maddison, Sarah; Wright, Chris M.; Wilner, David J.; Lommen, Dave J. P.; Koribalski, Baerbel

    2015-01-01

    We present new results from a radio monitoring survey conducted with ATCA where we measured the flux variability for 11 protoplanetary disks in the Chameoleon and Lupus star forming regions at 7 and 15 mm and 3+6 cm. We determined the source of the excess flux and discuss its effect on grain growth to cm-size pebbles. We found that for most targets the 7 mm flux variability is consistent with the presence of thermal free-free emission and that the targets with excess emission above thermal dust emission also have signatures of grain growth to cm-size pebbles. Our results indicate that the presence of other emission mechanisms does not seem to negatively affect the grain growth process.

  8. Monochromatic radio frequency accelerating cavity

    DOEpatents

    Giordano, Salvatore

    1985-01-01

    A radio frequency resonant cavity having a fundamental resonant frequency and characterized by being free of spurious modes. A plurality of spaced electrically conductive bars are arranged in a generally cylindrical array within the cavity to define a chamber between the bars and an outer solid cylindrically shaped wall of the cavity. A first and second plurality of mode perturbing rods are mounted in two groups at determined random locations to extend radially and axially into the cavity thereby to perturb spurious modes and cause their fields to extend through passageways between the bars and into the chamber. At least one body of lossy material is disposed within the chamber to damp all spurious modes that do extend into the chamber thereby enabling the cavity to operate free of undesired spurious modes.

  9. Monochromatic radio frequency accelerating cavity

    DOEpatents

    Giordano, S.

    1984-02-09

    A radio frequency resonant cavity having a fundamental resonant frequency and characterized by being free of spurious modes. A plurality of spaced electrically conductive bars are arranged in a generally cylindrical array within the cavity to define a chamber between the bars and an outer solid cylindrically shaped wall of the cavity. A first and second plurality of mode perturbing rods are mounted in two groups at determined random locations to extend radially and axially into the cavity thereby to perturb spurious modes and cause their fields to extend through passageways between the bars and into the chamber. At least one body of lossy material is disposed within the chamber to damp all spurious modes that do extend into the chamber thereby enabling the cavity to operate free of undesired spurious modes.

  10. A radio frequency coaxial feedthrough

    DOEpatents

    Owens, T.L.

    1987-12-07

    An improved radio frequency coaxial transmission line vacuum feedthrough is provided based on the use of a half-wavelength annular dielectric pressure barrier disk, or multiple disks comprising an effective half wavelength structure to eliminate reflection from the barrier surfaces. Gas-tight seals are formed about the outer and inner diameter surfaces of the barrier disk using a sealing technique which generates radial forces sufficient to form seals by forcing the conductor walls against the surfaces of the barrier disks in a manner which does not deform the radii of the inner and outer conductors, thereby preventing enhancement of the electric field at the barrier faces which limits the voltage and power handling capabilities of a feedthrough.

  11. Direct Broadcast Satellite: Radio Program

    NASA Technical Reports Server (NTRS)

    Hollansworth, James E.

    1992-01-01

    NASA is committed to providing technology development that leads to the introduction of new commercial applications for communications satellites. The Direct Broadcast Satellite-Radio (DBS-R) Program is a joint effort between The National Aeronautics and Space Administration (NASA) and The United States Information Agency/Voice of America (USIA/VOA) directed at this objective. The purpose of this program is to define the service and develop the technology for a direct-to-listener satellite sound broadcasting system. The DBS-R Program, as structured by NASA and VOA, is now a three-phase program designed to help the U.S. commercial communications satellite and receiver industry bring about this new communications service. Major efforts are being directed towards frequency planning hardware and service development, service demonstration, and experimentation with new satellite and receiver technology.

  12. Radio emission from AM Herculis

    NASA Technical Reports Server (NTRS)

    Bastian, T. S.; Dulk, G. A.; Chanmugam, G.

    1985-01-01

    Observations of the quiescent microwave emission of the magnetic cataclysmic variable AM Herculis are presented. The emission, which declined from a mean value of 0.58 mJy at 4.9 GHz to about 0.3 mJy, in rough coincidence with the entry of AM Herculis into an optical low state (mid-1983), is explained in terms of optically thick gyrosynchrotron emission. It is noted that the observation of a coherent outburst at 4.9 GHz, interpreted as the result of a cyclotron maser on the red dwarf secondary, indicates that the secondary is magnetized. Possible implications are briefly explored. Comparisons between this system and other stellar continuum radio sources are made.

  13. WHIM Environment of Giant Radio Galaxies

    NASA Astrophysics Data System (ADS)

    Subrahmanyan, R.; Saripalli, L.; Safouris, V.; Hunstead, R. W.

    2008-08-01

    Simulation studies of the warm-hot intergalactic medium (WHIM) suggest that about half of the baryons at low redshifts---the `missing baryons'---reside in a warm-hot phase. This gas is expected to occupy the intergalactic space in unvirialized and moderate overdensities associated with the large scale structure in the universe. Direct detection of these baryons is difficult, and progress in our understanding of the state of the WHIM requires observational probes of the diffuse gas associated with filaments and sheets. Radio continuum images of the radio galaxy MSH J0505-2835 have been made using the Very Large Array (VLA). The double radio structure of this giant radio source has a projected linear size of 1.8 Mpc, extends well beyond the interstellar medium and any coronal halo associated with the host elliptical galaxy and is interacting with the ambient intergalactic medium. We have examined the 3-D structure in the large scale galaxy distribution in the vicinity of the radio source. The host elliptical galaxy is a member of a sheet-like galaxy overdensity that has a fractional density contrast of order 10. The radio source is located at the boundary between this moderate overdensity and an adjacent void and, therefore, the radio lobes of this giant radio source represent an interaction with ambient WHIM gas. We present a novel method for estimating the properties of the WHIM. The radio data have been used to infer the evolution in the radio source. A lower limit of 4 × 10-15 N m-2 is derived for the pressure in the synchrotron-emitting gas in the lobes of the radio source, which leads to an estimate of 3 × 108 K m-3 for the density-temperature product in the ambient WHIM. Assuming that galaxies trace the unseen WHIM gas in these large-scale structures that represent moderate overdensities, the densities and temperatures we may expect for the ambient WHIM environment---based on the local galaxy overdensity and assuming that the WHIM gas is heated by

  14. From radio pulsars to rotating radio transients via magnetars

    NASA Astrophysics Data System (ADS)

    Konar, Sushan

    2012-07-01

    Recent observations suggest a possible evolutionary link between the rotation-powered pulsars (RPP) and the magnetars through glitch-induced increase in the surface magnetic fields of RPPs. PSR J1846-0258, observed to exhibit transient magnetar-like activity accompanied by a giant glitch~(Livingstone et al. 2011) is likely undergoing a transition from the RPP phase. On the other hand, it is possible that magnetars show up as rotating radio transients (RRAT) through a rapid field decay like in the case of RRAT J1819-1459 ~(Lyne et al. 2009). In the present work, we investigate a possible evolutionary route from RPPs to RRATs via magnetars. The magnetic field of a neutron star is generally understood to thread the superfluid core in the form of Abrikosov flux tubes. We postulate that a super-strong magnetic field residing in the core of a radio pulsar is completely/partially screened by some form of screening currents at the core-crust boundary. Glitches of large magnitudes (mostly seen in young, high magnetic field pulsars) are capable of crust-cracking and thereby inducing a decay of this screening current which would result in an increase in the observable field at the surface. On the other hand rapid spin-down (also glitches) would give rise to an expulsion of magnetic flux from the superconducting core to the metallic crust. We model this expelled flux. It is also understood that the crust of a young, high-magnetic field pulsar undergoing frequent glitches would have very high impurity/defect content. We find that the magnetic flux expelled to this 'impure' crust undergoes rapid dissipation resulting in the transition of a magnetar into an RRAT. Livingstone, Margaret A.; Ng, C.-Y.; Kaspi, Victoria M.; Gavriil, Fotis P.; Gotthelf, E. V., 2011, ApJ, 730, 66 Lyne, A. G.; McLaughlin, M. A.; Keane, E. F.; Kramer, M.; Espinoza, C. M.; Stappers, B. W.; Palliyaguru, N. T.; Miller, J., 2009, MNRAS, 400, 1439

  15. Grote Reber, Radio Astronomy Pioneer, Dies

    NASA Astrophysics Data System (ADS)

    2002-12-01

    Grote Reber, one of the earliest pioneers of radio astronomy, died in Tasmania on December 20, just two days shy of his 91st birthday. Reber was the first person to build a radio telescope dedicated to astronomy, opening up a whole new "window" on the Universe that eventually produced such landmark discoveries as quasars, pulsars and the remnant "afterglow" of the Big Bang. His self- financed experiments laid the foundation for today's advanced radio-astronomy facilities. Grote Reber Grote Reber NRAO/AUI photo "Radio astronomy has changed profoundly our understanding of the Universe and has earned the Nobel Prize for several major contributions. All radio astronomers who have followed him owe Grote Reber a deep debt for his pioneering work," said Dr. Fred Lo, director of the National Radio Astronomy Observatory (NRAO). "Reber was the first to systematically study the sky by observing something other than visible light. This gave astronomy a whole new view of the Universe. The continuing importance of new ways of looking at the Universe is emphasized by this year's Nobel Prizes in physics, which recognized scientists who pioneered X-ray and neutrino observations," Lo added. Reber was a radio engineer and avid amateur "ham" radio operator in Wheaton, Illinois, in the 1930s when he read about Karl Jansky's 1932 discovery of natural radio emissions coming from outer space. As an amateur operator, Reber had won awards and communicated with other amateurs around the world, and later wrote that he had concluded "there were no more worlds to conquer" in radio. Learning of Jansky's discovery gave Reber a whole new challenge that he attacked with vigor. Analyzing the problem as an engineer, Reber concluded that what he needed was a parabolic-dish antenna, something quite uncommon in the 1930s. In 1937, using his own funds, he constructed a 31.4-foot-diameter dish antenna in his back yard. The strange contraption attracted curious attention from his neighbors and became

  16. Monitoring Radio Frequency Interference in Southwest Virginia

    NASA Astrophysics Data System (ADS)

    Rapp, Steve

    2010-01-01

    The radio signals received from astronomical objects are extremely weak. Because of this, radio sources are easily shrouded by interference from devices such as satellites and cell phone towers. Radio astronomy is very susceptible to this radio frequency interference (RFI). Possibly even worse than complete veiling, weaker interfering signals can contaminate the data collected by radio telescopes, possibly leading astronomers to mistaken interpretations. To help promote student awareness of the connection between radio astronomy and RFI, an inquiry-based science curriculum was developed to allow high school students to determine RFI levels in their communities. The Quiet Skies Project_the result of a collaboration between the National Aeronautics and Space Administration (NASA), the National Science Foundation (NSF), and the National Radio Astronomy Observatory (NRAO)_encourages students to collect and analyze RFI data and develop conclusions as a team. Because the project focuses on electromagnetic radiation, it is appropriate for physics, physical science, chemistry, or general science classes. My class-about 50 students from 15 southwest Virginia high schools-participated in the Quiet Skies Project and were pioneers in the use of the beta version of the Quiet Skies Detector (QSD), which is used to detect RFI. Students have been involved with the project since 2005 and have collected and shared data with NRAO. In analyzing the data they have noted some trends in RFI in Southwest Virginia.

  17. The reproducible radio outbursts of SS Cygni

    NASA Astrophysics Data System (ADS)

    Russell, T. D.; Miller-Jones, J. C. A.; Sivakoff, G. R.; Altamirano, D.; O'Brien, T. J.; Page, K. L.; Templeton, M. R.; Körding, E. G.; Knigge, C.; Rupen, M. P.; Fender, R. P.; Heinz, S.; Maitra, D.; Markoff, S.; Migliari, S.; Remillard, R. A.; Russell, D. M.; Sarazin, C. L.; Waagen, E. O.

    2016-08-01

    We present the results of our intensive radio observing campaign of the dwarf nova SS Cyg during its 2010 April outburst. We argue that the observed radio emission was produced by synchrotron emission from a transient radio jet. Comparing the radio light curves from previous and subsequent outbursts of this system (including high-resolution observations from outbursts in 2011 and 2012) shows that the typical long and short outbursts of this system exhibit reproducible radio outbursts that do not vary significantly between outbursts, which is consistent with the similarity of the observed optical, ultraviolet and X-ray light curves. Contemporaneous optical and X-ray observations show that the radio emission appears to have been triggered at the same time as the initial X-ray flare, which occurs as disk material first reaches the boundary layer. This raises the possibility that the boundary region may be involved in jet production in accreting white dwarf systems. Our high spatial resolution monitoring shows that the compact jet remained active throughout the outburst with no radio quenching.

  18. The reproducible radio outbursts of SS Cygni

    NASA Astrophysics Data System (ADS)

    Russell, T. D.; Miller-Jones, J. C. A.; Sivakoff, G. R.; Altamirano, D.; O'Brien, T. J.; Page, K. L.; Templeton, M. R.; Körding, E. G.; Knigge, C.; Rupen, M. P.; Fender, R. P.; Heinz, S.; Maitra, D.; Markoff, S.; Migliari, S.; Remillard, R. A.; Russell, D. M.; Sarazin, C. L.; Waagen, E. O.

    2016-08-01

    We present the results of our intensive radio observing campaign of the dwarf nova SS Cyg during its 2010 April outburst. We argue that the observed radio emission was produced by synchrotron emission from a transient radio jet. Comparing the radio light curves from previous and subsequent outbursts of this system (including high-resolution observations from outbursts in 2011 and 2012) shows that the typical long and short outbursts of this system exhibit reproducible radio outbursts that do not vary significantly between outbursts, which is consistent with the similarity of the observed optical, ultraviolet and X-ray light curves. Contemporaneous optical and X-ray observations show that the radio emission appears to have been triggered at the same time as the initial X-ray flare, which occurs as disc material first reaches the boundary layer. This raises the possibility that the boundary region may be involved in jet production in accreting white dwarf systems. Our high spatial resolution monitoring shows that the compact jet remained active throughout the outburst with no radio quenching.

  19. DIFFUSIVE SHOCK ACCELERATION SIMULATIONS OF RADIO RELICS

    SciTech Connect

    Kang, Hyesung; Ryu, Dongsu; Jones, T. W. E-mail: ryu@canopus.cnu.ac.kr

    2012-09-01

    Recent radio observations have identified a class of structures, so-called radio relics, in clusters of galaxies. The radio emission from these sources is interpreted as synchrotron radiation from GeV electrons gyrating in {mu}G-level magnetic fields. Radio relics, located mostly in the outskirts of clusters, seem to associate with shock waves, especially those developed during mergers. In fact, they seem to be good structures to identify and probe such shocks in intracluster media (ICMs), provided we understand the electron acceleration and re-acceleration at those shocks. In this paper, we describe time-dependent simulations for diffusive shock acceleration at weak shocks that are expected to be found in ICMs. Freshly injected as well as pre-existing populations of cosmic-ray (CR) electrons are considered, and energy losses via synchrotron and inverse Compton are included. We then compare the synchrotron flux and spectral distributions estimated from the simulations with those in two well-observed radio relics in CIZA J2242.8+5301 and ZwCl0008.8+5215. Considering that CR electron injection is expected to be rather inefficient at weak shocks with Mach number M {approx}< a few, the existence of radio relics could indicate the pre-existing population of low-energy CR electrons in ICMs. The implication of our results on the merger shock scenario of radio relics is discussed.

  20. SEYFERT GALAXIES: NUCLEAR RADIO STRUCTURE AND UNIFICATION

    SciTech Connect

    Lal, Dharam V.; Shastri, Prajval; Gabuzda, Denise C.

    2011-04-10

    A radio study of a carefully selected sample of 20 Seyfert galaxies that are matched in orientation-independent parameters, which are measures of intrinsic active galactic nucleus power and host galaxy properties, is presented to test the predictions of the unified scheme hypothesis. Our sample sources have core flux densities greater than 8 mJy at 5 GHz on arcsec scales due to the feasibility requirements. These simultaneous parsec-scale and kiloparsec-scale radio observations reveal (1) that Seyfert 1 and Seyfert 2 galaxies have an equal tendency to show compact radio structures on milliarcsecond scales, (2) the distributions of parsec-scale and kiloparsec-scale radio luminosities are similar for both Seyfert 1 and Seyfert 2 galaxies, (3) there is no evidence for relativistic beaming in Seyfert galaxies, (4) similar distributions of source spectral indices in spite of the fact that Seyferts show nuclear radio flux density variations, and (5) the distributions of the projected linear size for Seyfert 1 and Seyfert 2 galaxies are not significantly different as would be expected in the unified scheme. The latter could be mainly due to a relatively large spread in the intrinsic sizes. We also find that a starburst alone cannot power these radio sources. Finally, an analysis of the kiloparsec-scale radio properties of the CfA Seyfert galaxy sample shows results consistent with the predictions of the unified scheme.

  1. The radio source around Eta Carinae

    NASA Technical Reports Server (NTRS)

    White, S. M.; Duncan, R. A.; Lim, J.; Nelson, G. J.; Drake, S. A.; Kundu, M. R.

    1994-01-01

    We present high spatial resolution radio observations of the peculiar southern star Eta Carinae, made with the Australian Telescope. The images, at 8 and 9 GHz with a resolution of 1.0 arcsec show a source of dimension 10 arcsec and total flux of 0.7 Jy dominated by a strong central peak. The radio emission is unpolarized and offers no support to models which invoke degenerate stars or more exotic objects within the core of Eta Car. In these data we find no evidence for more than one energy source in the core with arcsecond separations as some infrared observations have suggested. Several levels of structure are evident in the radio image, which shows symmetry on the larger scales. Conventional formulae for stellar wind radio sources give a mass loss rate of order 3 x 10(exp -4) Solar Mass/yr based on the radio flux in the central peak, which yields a wind momentum flux of order 20% of the momentum flux available from the star's radiation field. The radio emission at these frequencies is consistent with thermal emission from gas flowing away from a 'luminous blue variable' star (LBV) Eta Car is probably the brightest thermal stellar wind radio source in the sky.

  2. Radio Flares from Gamma-ray Bursts

    NASA Astrophysics Data System (ADS)

    Kopač, D.; Mundell, C. G.; Kobayashi, S.; Virgili, F. J.; Harrison, R.; Japelj, J.; Guidorzi, C.; Melandri, A.; Gomboc, A.

    2015-06-01

    We present predictions of centimeter and millimeter radio emission from reverse shocks (RSs) in the early afterglows of gamma-ray bursts (GRBs) with the goal of determining their detectability with current and future radio facilities. Using a range of GRB properties, such as peak optical brightness and time, isotropic equivalent gamma-ray energy, and redshift, we simulate radio light curves in a framework generalized for any circumburst medium structure and including a parameterization of the shell thickness regime that is more realistic than the simple assumption of thick- or thin-shell approximations. Building on earlier work by Mundell et al. and Melandri et al. in which the typical frequency of the RS was suggested to lie at radio rather than optical wavelengths at early times, we show that the brightest and most distinct RS radio signatures are detectable up to 0.1-1 day after the burst, emphasizing the need for rapid radio follow-up. Detection is easier for bursts with later optical peaks, high isotropic energies, lower circumburst medium densities, and at observing frequencies that are less prone to synchrotron self-absorption effects—typically above a few GHz. Given recent detections of polarized prompt gamma-ray and optical RS emission, we suggest that detection of polarized radio/millimeter emission will unambiguously confirm the presence of low-frequency RSs at early time.

  3. Radio Science Measurements with Suppressed Carrier

    NASA Technical Reports Server (NTRS)

    Asmar, Sami; Divsalar, Dariush; Oudrhiri, Kamal

    2013-01-01

    Radio Science started when it became apparent with early Solar missions that occultations by planetary atmospheres would affect the quality of radio communications. Since then the atmospheric properties and other aspects of planetary science, solar science, and fundamental physics were studied by scientists. Radio Science data was always extracted from a received pure residual carrier (without data modulation). For some missions, it is very desirable to obtain Radio Science data from a suppressed carrier modulation. In this paper we propose a method to extract Radio Science data when a coded suppressed carrier modulation is used in deep space communications. Type of modulation can be BPSK, QPSK, OQPSK, MPSK or even GMSK. However we concentrate mostly on BPSK modulation. The proposed method for suppressed carrier simply tries to wipe out data that acts as an interference for Radio Science measurements. In order to measure the estimation errors in amplitude and phase of the Radio Science data we use Cramer-Rao bound (CRB). The CRB for the suppressed carrier modulation with non-ideal data wiping is then compared with residual carrier modulation under the same noise condition. The method of derivation of CRB for non-ideal data wiping is an innovative method that presented here. Some numerical results are provided for coded system.

  4. Parallel computation of radio listening rates

    NASA Astrophysics Data System (ADS)

    Mazzariol, Marc; Gennart, Benoit A.; Hersch, Roger D.; Gomez, Manuel; Balsiger, Peter; Pellandini, Fausto; Leder, Markus; Wuethrich, Daniel; Feitknecht, Juerg

    2000-10-01

    Obtaining the listening rates of radio stations in function of time is an important instrument for determining the impact of publicity. Since many radio stations are financed by publicity, the exact determination of radio listening rates is vital to their existence and to further development. Existing methods of determining radio listening rates are based on face to face interviews or telephonic interviews made with a sample population. These traditional methods however require the cooperation and compliance of the participants. In order to significantly improve the determination of radio listening rates, special watches were created which incorporate a custom integrated circuit sampling the ambient sound during a few seconds every minutes. Each watch accumulates these compressed sound samples during one full week. Watches are then sent to an evaluation center, where the sound samples are matched with the sound samples recorded from candidate radio stations. The present paper describes the processing steps necessary for computing the radio listening rates, and shows how this application was parallelized on a cluster of PCs using the CAP Computer-aided parallelization framework. Since the application must run in a production environment, the paper describes also the support provided for graceful degradation in case of transient or permanent failure of one of the system's components. The parallel sound matching server offers a linear speedup up to a large number of processing nodes thanks to the fact that disk access operations across the network are done in pipeline with computations.

  5. THE FUNDAMENTAL PLANE FOR RADIO MAGNETARS

    SciTech Connect

    Rea, Nanda; Torres, Diego F.; Pons, Jose A.; Turolla, Roberto

    2012-03-20

    High magnetic fields are a distinguishing feature of neutron stars and the existence of sources (the soft gamma repeaters, SGRs, and the anomalous X-ray pulsars) hosting an ultramagnetized neutron star (or magnetar) has been recognized in the past few decades. Magnetars are believed to be powered by magnetic energy and not by rotation, as with normal radio pulsars. Until recently, the radio quietness and magnetic fields typically above the quantum critical value (B{sub Q} {approx_equal} 4.4 Multiplication-Sign 10{sup 13} G) were among the characterizing properties of magnetars. The recent discovery of radio-pulsed emission from a few of them, and of a low dipolar magnetic field SGR, weakened further the idea of a clean separation between normal pulsars and magnetars. In this Letter, we show that radio emission from magnetars might be powered by rotational energy, similarly to what occurs in normal radio pulsars. The peculiar characteristics of magnetars radio emission should be traced in the complex magnetic geometry of these sources. Furthermore, we propose that magnetar radio activity or inactivity can be predicted from the knowledge of the star's rotational period, its time derivative, and the quiescent X-ray luminosity.

  6. Amateur Planetary Radio Data Archived for Science and Education: Radio Jove

    NASA Astrophysics Data System (ADS)

    Thieman, J.; Cecconi, B.; Sky, J.; Garcia, L. N.; King, T. A.; Higgins, C. A.; Fung, S. F.

    2015-12-01

    The Radio Jove Project is a hands-on educational activity in which students, teachers, and the general public build simple radio telescopes, usually from a kit, to observe single frequency decameter wavelength radio emissions from Jupiter, the Sun, the galaxy, and the Earth usually with simple dipole antennas. Some of the amateur observers have upgraded their receivers to spectrographs and their antennas have become more sophisticated as well. The data records compare favorably to more sophisticated professional radio telescopes such as the Long Wavelength Array (LWA) and the Nancay Decametric Array. Since these data are often carefully calibrated and recorded around the clock in widely scattered locations they represent a valuable database useful not only to amateur radio astronomers but to the professional science community as well. Some interesting phenomena have been noted in the data that are of interest to the professionals familiar with such records. The continuous monitoring of radio emissions from Jupiter could serve as useful "ground truth" data during the coming Juno mission's radio observations of Jupiter. Radio Jove has long maintained an archive for thousands of Radio Jove observations, but the database was intended for use by the Radio Jove participants only. Now, increased scientific interest in the use of these data has resulted in several proposals to translate the data into a science community data format standard and store the data in professional archives. Progress is being made in translating Radio Jove data to the Common Data Format (CDF) and also in generating new observations in that format as well. Metadata describing the Radio Jove data would follow the Space Physics Archive Search and Extract (SPASE) standard. The proposed archive to be used for long term preservation would be the Planetary Data System (PDS). Data sharing would be achieved through the PDS and the Paris Astronomical Data Centre (PADC) and the Virtual Wave Observatory (VWO

  7. Spacecraft Radio Scintillation and Solar System Exploration

    NASA Technical Reports Server (NTRS)

    Woo, Richard

    1993-01-01

    When a wave propagates through a turbulent medium, scattering by the random refractive index inhomogeneities can lead to a wide variety of phenomena that have been the subject of extensive study. The observed scattering effects include amplitude or intensity scintillation, phase scintillation, angular broadening, and spectral broadening, among others. In this paper, I will refer to these scattering effects collectively as scintillation. Although the most familiar example is probably the twinkling of stars (light wave intensity scintillation by turbulence in the Earth's atmosphere), scintillation has been encountered and investigated in such diverse fields as ionospheric physics, oceanography, radio astronomy, and radio and optical communications. Ever since planetary spacecraft began exploring the solar system, scintillation has appeared during the propagation of spacecraft radio signals through planetary atmospheres, planetary ionospheres, and the solar wind. Early studies of these phenomena were motivated by the potential adverse effects on communications and navigation, and on experiments that use the radio link to conduct scientific investigations. Examples of the latter are radio occultation measurements (described below) of planetary atmospheres to deduce temperature profiles, and the search for gravitational waves. However,these concerns soon gave way to the emergence of spacecraft radio scintillation as a new scientific tool for exploring small-scale dynamics in planetary atmospheres and structure in the solar wind, complementing in situ and other remote sensing spacecraft measurements, as well as scintillation measurements using natural (celestial) radio sources. The purpose of this paper is to briefly describe and review the solar system spacecraft radio scintillation observations, to summarize the salient features of wave propagation analyses employed in interpreting them, to underscore the unique remote sensing capabilities and scientific relevance of

  8. Steep radio spectra in high-redshift radio galaxies

    NASA Technical Reports Server (NTRS)

    Krolik, Julian H.; Chen, Wan

    1991-01-01

    The generic spectrum of an optically thin synchrotron source steepens by 0.5 in spectral index from low frequencies to high whenever the source lifetime is greater than the energy-loss timescale for at least some of the radiating electrons. Three effects tend to decrease the frequency nu(b) of this spectral bend as the source redshift increases: (1) for fixed bend frequency nu* in the rest frame, nu(b) = nu*/(1 + z); (2) losses due to inverse Compton scattering the microwave background rise with redshift as (1 + z) exp 4, so that, for fixed residence time in the radiating region, the energy of the lowest energy electron that can cool falls rapidly with increasing redshift; and (3) if the magnetic field is proportional to the equipartition field and the emitting volume is fixed or slowly varying, flux-limited samples induce a selection effect favoring low nu* at high z because higher redshift sources require higher emissivity to be included in the sample, and hence have stronger implied fields and more rapid synchrotron losses. A combination of these effects may explain the trend observed in the 3CR sample for higher redshift radio galaxies to have steeper spectra, and the successful use of ultrasteep spectrum surveys to locate high-redshift galaxies.

  9. ARCADE Detection of an Extragalactic Radio Background

    NASA Technical Reports Server (NTRS)

    Kogut, Alan J.

    2009-01-01

    Sometimes when we look for one thing we stumble on something else. The Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission (ARCADE) was designed to measure the blackbody spectrum of the cosmic microwave background to search for spectral distortions related to the epoch of reionization. Instead, the July 2006 flight found evidence for an extragalactic radio background with amplitude six times brighter than the expected contribution from faint radio sources. The author discusses the ARCADE instrument and the evidence for an extragalactic radio background.

  10. Radio emissions and the heliospheric termination shock

    NASA Technical Reports Server (NTRS)

    Zank, G. P.; Cairns, I. H.; Donohue, D. J.; Matthaeus, W. H.

    1994-01-01

    With the Voyager spacecrafts' discovery of low-frequency radio emissions from the depths of the outer heliosphere has come the realization that the boundaries between our heliosphere and the local interstellar medium have been detected. A model is presented here that can account for the observed radio emissions, based upon a termination shock modified by the dynamical effect of galactic and anomalous cosmic rays. Frequency and time domain properties of both continuum and transient radio events are explained, and new estimates for the distance to the termination shock (approximately 60-70 astronomical units) and the heliopause (less than or approximately 90 AU) are given.

  11. Speckles in interstellar radio-wave scattering

    NASA Technical Reports Server (NTRS)

    Desai, K. M.; Gwinn, C. R.; Reynolds, J.; King, E. A.; Jauncey, D.; Nicholson, G.; Flanagan, C.; Preston, R. A.; Jones, D. L.

    1991-01-01

    Observations of speckles in the scattering disk of the Vela pulsar are presented and speckle techniques for studying and circumventing scattering of radio waves by the turbulent interstellar plasma are discussed. The speckle pattern contains, in a hologrammatic fashion, complete information on the structure of the radio source as well as the distribution of the scattering material. Speckle observations of interstellar scattering of radio waves are difficult because of their characteristically short timescales and narrow bandwidths. Here, first observations are presented, taken at 13 cm wavelength with elements of the SHEVE VLBI network, of speckles in interstellar scattering.

  12. Radio-protective role of antioxidant agents

    PubMed Central

    Shirazi, Alireza; Mihandoost, Ehsan; Mahdavi, Seied Rabie; Mohseni, Mehran

    2012-01-01

    Ionizing radiation interacts with biological systems to produce reactive oxygen species and reactive nitrogen species which attack various cellular components. Radio-protectors act as prophylactic agents to shield healthy cells and tissues from the harmful effects of radiation. Past research on synthetic radio-protectors has brought little success, primarily due to the various toxicity-related problems. Results of experimental research show that antioxidant nutrients, such as vitamin E and herbal products and melatonin, are protective against the damaging effects of radiation, with less toxicity and side effects. Therefore, we propose that in the future, antioxidant radio-protective agents may improve the therapeutic index in radiation oncology treatments. PMID:25992214

  13. Optical identifications of southern compact radio sources

    NASA Technical Reports Server (NTRS)

    Jauncey, David L.; Savage, Ann; Morabito, David D.; Preston, Robert A.; Nicolson, George C.

    1989-01-01

    Optical identifications are presented for 158 radio sources, mostly from the Southern Hemisphere, based on the coincidence between the position of the optical object and the compact milliarcsecond radio nucleus. Radio positions with an accuracy of typically 0.3 arcsec rms were measured from the observed delay and fringe rate of VLBI observations at 2.29 GHz on an Australia-to-South Africa baseline. Optical identifications and positions were measured from the UK Schmidt Telescope deep IIIa-J Southern Sky Survey plates, where available.

  14. Parsec-scale radio structures in Quasars

    NASA Astrophysics Data System (ADS)

    Coldwell, G.; Paragi, Z.; Gurvits, L.

    Very Long Baseline Interferometry (VLBI) con su nueva extensión para el radio telescopio orbital, VSOP/HALCA, ofrece una incomparable resolución angular alcanzando escalas de milisegundos y submilisegundos de arco a longitudes de onda de centímetros. En este trabajo presentamos observaciones y análisis de estructuras en radio, en escalas de parsec, para 3 radio fuentes extragalácticas de la muestra de VSOP Survey y 1 quasar, 1442+101, del proyecto `VSOP High Redshift'.

  15. Application of mesh network radios to UGS

    NASA Astrophysics Data System (ADS)

    Calcutt, Wade; Jones, Barry; Roeder, Brent

    2008-04-01

    During the past five years McQ has been actively pursuing integrating and applying wireless mesh network radios as a communications solution for unattended ground sensor (UGS) systems. This effort has been rewarded with limited levels of success and has ultimately resulted in a corporate position regarding the use of mesh network radios for UGS systems. A discussion into the background of the effort, the challenges of implementing commercial off-the-shelf (COTS) mesh radios with UGSs, the tradeoffs involved, and an overview of the future direction is presented.

  16. Python Ephemeris Module for Radio Astronomy

    NASA Astrophysics Data System (ADS)

    Kuiper, T. B.

    2013-05-01

    An extension of the Python pyephem module was developed for Deep Space Network (DSN) radio astronomy. The class DSS( ) provides the geodetic coordinates of the DSN stations as well as other properties such as antenna diameter. The class Quasar( ) provides positional data for the sources in the National Radio Astronomy Observatory Very Large Array (NRAO VLA) Calibrator Handbook and flux estimates based the University of Michigan Radio Astronomy Observatory (UMRAO) Database or the VLA Calibrator Handbook. Flux calibration data are also available for the bright planets. Class Pulsar( ) provides the data from the Australia Telescope National Facility (ATNF) Pulsar Catalogue in Python format.

  17. Multi-mode radio frequency device

    DOEpatents

    Gilbert, Ronald W.; Carrender, Curtis Lee; Anderson, Gordon A.; Steele, Kerry D.

    2007-02-13

    A transponder device having multiple modes of operation, such as an active mode and a passive mode, wherein the modes of operation are selected in response to the strength of a received radio frequency signal. A communication system is also provided having a transceiver configured to transmit a radio frequency signal and to receive a responsive signal, and a transponder configured to operate in a plurality of modes and to activate modes of operation in response to the radio frequency signal. Ideally, each mode of operation is activated and deactivated independent of the other modes, although two or more modes may be concurrently operational.

  18. High power radio frequency attenuation device

    DOEpatents

    Kerns, Quentin A.; Miller, Harold W.

    1984-01-01

    A resistor device for attenuating radio frequency power includes a radio frequency conductor connected to a series of fins formed of high relative magnetic permeability material. The fins are dimensional to accommodate the skin depth of the current conduction therethrough, as well as an inner heat conducting portion where current does not travel. Thermal connections for air or water cooling are provided for the inner heat conducting portions of each fin. Also disclosed is a resistor device to selectively alternate unwanted radio frequency energy in a resonant cavity.

  19. Testbed System of Inter-Radio System Switching for Cognitive Radio

    NASA Astrophysics Data System (ADS)

    Hanaoka, Seishi; Yano, Masashi; Hirata, Tetsuhiko

    The cognitive radio system consists of multiple wireless access systems that cover overlapping areas and cognitive terminals that use one or more of the wireless accesses simultaneously. In this paper, we describe the architecture of the cognitive radio system and the inter-system handover protocols. In the architecture, each cognitive terminal, which can access multiple radio systems, operates with a single local IP address. The control sequence and packet format are designed to achieve fast handover among the radio systems. Based on the architecture, we have developed a testbed system. On this system, we demonstrate that data can be delivered continuously and radio systems can be switched correctly without any packet loss. In addition, we present the result of the evaluation of the end-to-end latency on the testbed system. These testbed results demonstrate the system architecture described in the paper can achieve a cognitive radio system.

  20. Covering factors of the dusty obscurers in radio-loud and radio-quiet quasars

    NASA Astrophysics Data System (ADS)

    Gupta, Maitrayee; Sikora, Marek; Nalewajko, Krzysztof

    2016-09-01

    We compare covering factors of circumnuclear dusty obscurers in radio-loud and radio-quiet quasars. The radio-loud quasars are represented by a sample of FR II quasars obtained by cross-matching a catalog of the FR II radio sources selected by van Velzen et al. with the SDSS DR7 catalog of quasars. Covering factors of FR II quasars are compared with covering factors of the radio-quiet quasars matched with them in redshift, black hole mass, and Eddington-ratio. We found that covering factors, proxied by the infrared-to-bolometric luminosity ratio, are on average slightly smaller in FR II quasars than in radio-quiet quasars, however, this difference is statistically significant only for the highest Eddington ratios. For both samples, no statistically significant dependence of a median covering factor on Eddington ratio, black hole mass, nor redshift can be claimed.

  1. 47 CFR 2.815 - External radio frequency power amplifiers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false External radio frequency power amplifiers. 2... External radio frequency power amplifiers. (a) As used in this part, an external radio frequency power amplifier is any device which, (1) when used in conjunction with a radio transmitter as a signal source...

  2. 47 CFR 2.815 - External radio frequency power amplifiers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false External radio frequency power amplifiers. 2... External radio frequency power amplifiers. (a) As used in this part, an external radio frequency power amplifier is any device which, (1) when used in conjunction with a radio transmitter as a signal source...

  3. 47 CFR 2.815 - External radio frequency power amplifiers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false External radio frequency power amplifiers. 2... External radio frequency power amplifiers. (a) As used in this part, an external radio frequency power amplifier is any device which, (1) when used in conjunction with a radio transmitter as a signal source...

  4. 47 CFR 2.815 - External radio frequency power amplifiers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false External radio frequency power amplifiers. 2... External radio frequency power amplifiers. (a) As used in this part, an external radio frequency power amplifier is any device which, (1) when used in conjunction with a radio transmitter as a signal source...

  5. 47 CFR 2.815 - External radio frequency power amplifiers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false External radio frequency power amplifiers. 2... External radio frequency power amplifiers. (a) As used in this part, an external radio frequency power amplifier is any device which, (1) when used in conjunction with a radio transmitter as a signal source...

  6. 47 CFR 90.241 - Radio call box operations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Radio call box operations. 90.241 Section 90.241 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Non-Voice and Other Specialized Operations § 90.241 Radio call box operations. (a) The frequencies in the 72-76...

  7. 47 CFR 90.241 - Radio call box operations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Radio call box operations. 90.241 Section 90.241 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Non-Voice and Other Specialized Operations § 90.241 Radio call box operations. (a) The frequencies in the 72-76...

  8. Memo to All Young People Interested in Radio.

    ERIC Educational Resources Information Center

    Federal Communications Commission, Washington, DC.

    Unlicensed radio operation may interfere with regular broadcast reception and radio communication for safety services. In this bulletin, the Federal Communications Commission (FCC) advises teenagers not to violate the law, but to pursue their interest in radio broadcast by joining the Amateur Radio Service or qualifying for a commercial permit.…

  9. 47 CFR 90.241 - Radio call box operations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Radio call box operations. 90.241 Section 90.241 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Non-Voice and Other Specialized Operations § 90.241 Radio call box operations. (a) The frequencies in the 72-76...

  10. 47 CFR 2.107 - Radio astronomy station notification.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Radio astronomy station notification. 2.107....107 Radio astronomy station notification. (a) Pursuant to No. 1492 of Article 13 and Section F of Appendix 3 to the international Radio Regulations (Geneva, 1982), operators of radio astronomy...

  11. 47 CFR 2.107 - Radio astronomy station notification.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Radio astronomy station notification. 2.107....107 Radio astronomy station notification. (a) Pursuant to No. 1492 of Article 13 and Section F of Appendix 3 to the international Radio Regulations (Geneva, 1982), operators of radio astronomy...

  12. 47 CFR 2.107 - Radio astronomy station notification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Radio astronomy station notification. 2.107....107 Radio astronomy station notification. (a) Pursuant to No. 1492 of Article 13 and Section F of Appendix 3 to the international Radio Regulations (Geneva, 1982), operators of radio astronomy...

  13. 47 CFR 2.107 - Radio astronomy station notification.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Radio astronomy station notification. 2.107....107 Radio astronomy station notification. (a) Pursuant to No. 1492 of Article 13 and Section F of Appendix 3 to the international Radio Regulations (Geneva, 1982), operators of radio astronomy...

  14. 47 CFR 2.107 - Radio astronomy station notification.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Radio astronomy station notification. 2.107....107 Radio astronomy station notification. (a) Pursuant to No. 1492 of Article 13 and Section F of Appendix 3 to the international Radio Regulations (Geneva, 1982), operators of radio astronomy...

  15. 47 CFR 2.944 - Software defined radios.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Software defined radios. 2.944 Section 2.944... Authorization § 2.944 Software defined radios. (a) Manufacturers must take steps to ensure that only software that has been approved with a software defined radio can be loaded into the radio. The software...

  16. 47 CFR 2.944 - Software defined radios.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Software defined radios. 2.944 Section 2.944... Authorization § 2.944 Software defined radios. (a) Manufacturers must take steps to ensure that only software that has been approved with a software defined radio can be loaded into the radio. The software...

  17. 47 CFR 2.944 - Software defined radios.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Software defined radios. 2.944 Section 2.944... Authorization § 2.944 Software defined radios. (a) Manufacturers must take steps to ensure that only software that has been approved with a software defined radio can be loaded into the radio. The software...

  18. 47 CFR 2.944 - Software defined radios.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Software defined radios. 2.944 Section 2.944... Authorization § 2.944 Software defined radios. (a) Manufacturers must take steps to ensure that only software that has been approved with a software defined radio can be loaded into the radio. The software...

  19. 49 CFR 220.23 - Publication of radio information.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Publication of radio information. 220.23 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.23 Publication of radio information. Each railroad shall designate where radio base stations...

  20. 78 FR 4078 - Radio Broadcasting Services; Hebbronville, TX

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-18

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Hebbronville, TX AGENCY: Federal Communications... Review Act, see 5 U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting...: PART 73--RADIO BROADCAST SERVICES 0 1. The authority citation for part 73 continues to read as...

  1. 47 CFR 95.628 - MedRadio transmitters.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false MedRadio transmitters. 95.628 Section 95.628 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Technical Regulations Technical Standards § 95.628 MedRadio transmitters. (a) Frequency...

  2. 47 CFR 80.289 - Requirements for radio direction finder.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Requirements for radio direction finder. 80.289 Section 80.289 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO... Requirements for radio direction finder. (a) The radio direction finding apparatus must: (1) Be capable...

  3. 49 CFR 220.47 - Emergency radio transmissions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Emergency radio transmissions. 220.47 Section 220... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.47 Emergency radio transmissions. An initial emergency radio transmission shall be preceded by...

  4. 49 CFR 220.47 - Emergency radio transmissions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Emergency radio transmissions. 220.47 Section 220... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.47 Emergency radio transmissions. An initial emergency radio transmission shall be preceded by...

  5. 49 CFR 220.31 - Initiating a radio transmission.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Initiating a radio transmission. 220.31 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.31 Initiating a radio transmission. Before transmitting by radio, an employee shall: (a) Listen...

  6. 47 CFR 97.407 - Radio amateur civil emergency service.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Radio amateur civil emergency service. 97.407 Section 97.407 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO SERVICE Providing Emergency Communications § 97.407 Radio amateur civil...

  7. 49 CFR 220.31 - Initiating a radio transmission.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Initiating a radio transmission. 220.31 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.31 Initiating a radio transmission. Before transmitting by radio, an employee shall: (a) Listen...

  8. 49 CFR 220.33 - Receiving a radio transmission.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Receiving a radio transmission. 220.33 Section 220... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.33 Receiving a radio transmission. (a) Upon receiving a radio call, an employee shall...

  9. 49 CFR 220.45 - Radio communication shall be complete.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Radio communication shall be complete. 220.45... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.45 Radio communication shall be complete. Any radio communication which is not fully understood...

  10. 49 CFR 220.39 - Continuous radio monitoring.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Continuous radio monitoring. 220.39 Section 220.39..., DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.39 Continuous radio monitoring. Each radio used in a railroad operation shall be turned on to the...

  11. 77 FR 32900 - Radio Broadcasting Services; Llano, TX

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-04

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Llano, TX AGENCY: Federal Communications Commission... Congressional Review Act, see U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting...: PART 73--RADIO BROADCAST SERVICES 0 1. The authority citation for part 73 continues to read as...

  12. 47 CFR 97.407 - Radio amateur civil emergency service.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Radio amateur civil emergency service. 97.407 Section 97.407 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO SERVICE Providing Emergency Communications § 97.407 Radio amateur civil...

  13. 47 CFR 0.484 - Amateur radio operator examinations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Amateur radio operator examinations. 0.484....484 Amateur radio operator examinations. Generally, examinations for amateur radio operation licenses... FCC conducts examinations for amateur radio operator licenses, they shall take place at locations...

  14. 49 CFR 220.23 - Publication of radio information.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Publication of radio information. 220.23 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.23 Publication of radio information. Each railroad shall designate where radio base stations...

  15. 49 CFR 220.45 - Radio communication shall be complete.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Radio communication shall be complete. 220.45... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.45 Radio communication shall be complete. Any radio communication which is not fully understood...

  16. 75 FR 41123 - Radio Broadcasting Services; Gearhart, OR

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-15

    ... COMMISSION 47 CFR Part 73 . Radio Broadcasting Services; Gearhart, OR AGENCY: Federal Communications... Radio, Radio broadcasting. For the reasons discussed in the preamble, the Federal Communications Commission proposes to amend 47 CFR Part 73 as follows: PART 73--RADIO BROADCAST SERVICES 1. The...

  17. 47 CFR 97.407 - Radio amateur civil emergency service.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Radio amateur civil emergency service. 97.407 Section 97.407 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO SERVICE Providing Emergency Communications § 97.407 Radio amateur civil...

  18. 49 CFR 220.47 - Emergency radio transmissions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Emergency radio transmissions. 220.47 Section 220... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.47 Emergency radio transmissions. An initial emergency radio transmission shall be preceded by...

  19. 49 CFR 220.33 - Receiving a radio transmission.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Receiving a radio transmission. 220.33 Section 220... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.33 Receiving a radio transmission. (a) Upon receiving a radio call, an employee shall...

  20. 47 CFR 80.289 - Requirements for radio direction finder.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Requirements for radio direction finder. 80.289 Section 80.289 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO... Requirements for radio direction finder. (a) The radio direction finding apparatus must: (1) Be capable...

  1. 47 CFR 80.289 - Requirements for radio direction finder.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Requirements for radio direction finder. 80.289 Section 80.289 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO... Requirements for radio direction finder. (a) The radio direction finding apparatus must: (1) Be capable...

  2. 49 CFR 220.23 - Publication of radio information.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Publication of radio information. 220.23 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.23 Publication of radio information. Each railroad shall designate where radio base stations...

  3. 49 CFR 220.39 - Continuous radio monitoring.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Continuous radio monitoring. 220.39 Section 220.39..., DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.39 Continuous radio monitoring. Each radio used in a railroad operation shall be turned on to the...

  4. 49 CFR 220.33 - Receiving a radio transmission.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Receiving a radio transmission. 220.33 Section 220... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.33 Receiving a radio transmission. (a) Upon receiving a radio call, an employee shall...

  5. 49 CFR 220.33 - Receiving a radio transmission.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Receiving a radio transmission. 220.33 Section 220... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.33 Receiving a radio transmission. (a) Upon receiving a radio call, an employee shall...

  6. 49 CFR 220.45 - Radio communication shall be complete.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Radio communication shall be complete. 220.45... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.45 Radio communication shall be complete. Any radio communication which is not fully understood...

  7. 77 FR 64946 - Radio Broadcasting Services; Maysville, Georgia

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-24

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Maysville, Georgia AGENCY: Federal Communications... Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief, Audio... proposes to amend 47 CFR part 73 as follows: PART 73--RADIO BROADCAST SERVICES 1. The authority...

  8. 49 CFR 220.23 - Publication of radio information.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Publication of radio information. 220.23 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.23 Publication of radio information. Each railroad shall designate where radio base stations...

  9. 78 FR 26739 - Radio Broadcasting Services; Ehrenberg, Arizona

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-08

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Ehrenberg, Arizona AGENCY: Federal Communications... Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez... Communications Commission proposes to amend 47 CFR Part 73 as follows: PART 73--RADIO BROADCAST SERVICES 0 1....

  10. 49 CFR 220.31 - Initiating a radio transmission.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Initiating a radio transmission. 220.31 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.31 Initiating a radio transmission. Before transmitting by radio, an employee shall: (a) Listen...

  11. 75 FR 52872 - Radio Broadcasting Services; Blythe, CA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-30

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Blythe, CA AGENCY: Federal Communications Commission. ACTION: Final rule. SUMMARY: The Audio Division, at the request of Prescott Valley Radio Broadcasting... Congressional Review Act, see U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio...

  12. 47 CFR 0.484 - Amateur radio operator examinations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Amateur radio operator examinations. 0.484....484 Amateur radio operator examinations. Generally, examinations for amateur radio operation licenses... FCC conducts examinations for amateur radio operator licenses, they shall take place at locations...

  13. 47 CFR 97.407 - Radio amateur civil emergency service.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Radio amateur civil emergency service. 97.407 Section 97.407 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO SERVICE Providing Emergency Communications § 97.407 Radio amateur civil...

  14. 78 FR 12622 - Radio Broadcasting Services; Greenup, IL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-25

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Greenup, IL AGENCY: Federal Communications Commission... a first and/or second NCE radio service to 67.5 percent (21,149 persons) of the total population of... 5 U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. ]...

  15. 49 CFR 220.39 - Continuous radio monitoring.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Continuous radio monitoring. 220.39 Section 220.39..., DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.39 Continuous radio monitoring. Each radio used in a railroad operation shall be turned on to the...

  16. 49 CFR 220.31 - Initiating a radio transmission.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Initiating a radio transmission. 220.31 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.31 Initiating a radio transmission. Before transmitting by radio, an employee shall: (a) Listen...

  17. 77 FR 50053 - Radio Broadcasting Services; Westley, CA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-20

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Westley, CA AGENCY: Federal Communications Commission... 73 Radio, Radio broadcasting. Federal Communications Commission. Peter H. Doyle, Chief, Audio... amends 47 CFR part 73 as follows: PART 73--RADIO BROADCAST SERVICES 0 1. The authority citation for...

  18. 49 CFR 220.47 - Emergency radio transmissions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Emergency radio transmissions. 220.47 Section 220... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.47 Emergency radio transmissions. An initial emergency radio transmission shall be preceded by...

  19. 49 CFR 220.47 - Emergency radio transmissions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Emergency radio transmissions. 220.47 Section 220... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.47 Emergency radio transmissions. An initial emergency radio transmission shall be preceded by...

  20. 49 CFR 220.23 - Publication of radio information.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Publication of radio information. 220.23 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.23 Publication of radio information. Each railroad shall designate where radio base stations...

  1. 49 CFR 220.45 - Radio communication shall be complete.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Radio communication shall be complete. 220.45... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.45 Radio communication shall be complete. Any radio communication which is not fully understood...

  2. 49 CFR 220.33 - Receiving a radio transmission.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Receiving a radio transmission. 220.33 Section 220... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.33 Receiving a radio transmission. (a) Upon receiving a radio call, an employee shall...

  3. 77 FR 59882 - Radio Broadcasting Services; Tignall, GA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-01

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Tignall, GA AGENCY: Federal Communications Commission... Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief, Audio... proposes to amend 47 CFR part 73 as follows: PART 73--RADIO BROADCAST SERVICES 1. The authority...

  4. 47 CFR 0.484 - Amateur radio operator examinations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Amateur radio operator examinations. 0.484....484 Amateur radio operator examinations. Generally, examinations for amateur radio operation licenses... FCC conducts examinations for amateur radio operator licenses, they shall take place at locations...

  5. 47 CFR 80.289 - Requirements for radio direction finder.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Requirements for radio direction finder. 80.289 Section 80.289 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO... Requirements for radio direction finder. (a) The radio direction finding apparatus must: (1) Be capable...

  6. 78 FR 36683 - Radio Broadcasting Services; Summit, Mississippi

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-19

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Summit, Mississippi AGENCY: Federal Communications... U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal...--RADIO BROADCAST SERVICES 0 1. The authority citation for part 73 continues to read as follows:...

  7. 47 CFR 80.289 - Requirements for radio direction finder.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Requirements for radio direction finder. 80.289 Section 80.289 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO... Requirements for radio direction finder. (a) The radio direction finding apparatus must: (1) Be capable...

  8. 47 CFR 0.484 - Amateur radio operator examinations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Amateur radio operator examinations. 0.484....484 Amateur radio operator examinations. Generally, examinations for amateur radio operation licenses... FCC conducts examinations for amateur radio operator licenses, they shall take place at locations...

  9. 47 CFR 0.484 - Amateur radio operator examinations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Amateur radio operator examinations. 0.484....484 Amateur radio operator examinations. Generally, examinations for amateur radio operation licenses... FCC conducts examinations for amateur radio operator licenses, they shall take place at locations...

  10. 77 FR 64758 - Radio Broadcasting Services; Randsburg, CA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-23

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Randsburg, CA AGENCY: Federal Communications... Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief, Audio... amends 47 CFR Part 73 as follows: PART 73--RADIO BROADCAST SERVICES 0 1. The authority citation for...

  11. 49 CFR 220.39 - Continuous radio monitoring.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Continuous radio monitoring. 220.39 Section 220.39..., DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.39 Continuous radio monitoring. Each radio used in a railroad operation shall be turned on to the...

  12. 49 CFR 220.45 - Radio communication shall be complete.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Radio communication shall be complete. 220.45... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.45 Radio communication shall be complete. Any radio communication which is not fully understood...

  13. 75 FR 82279 - Radio Broadcasting Services; Various Locations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-30

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Various Locations AGENCY: Federal Communications... Subjects in 47 CFR Part 73 Radio, Radio broadcasting. 0 As stated in the preamble, the Federal Communications Commission amends 47 CFR part 73 as follows: PART 73--RADIO BROADCASTING SERVICES 0 1....

  14. 78 FR 266 - Radio Broadcasting Services; Maysville, GA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-03

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Maysville, GA AGENCY: Federal Communications... Act, see 5 U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal...--RADIO BROADCAST SERVICES 0 1. The authority citation for part 73 continues to read as follows:...

  15. 77 FR 23203 - Radio Broadcasting Services; Summit, MS

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-18

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Summit, MS AGENCY: Federal Communications Commission... Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez... Communications Commission proposes to amend 47 CFR Part 73 as follows: PART 73--RADIO BROADCAST SERVICES 1....

  16. 49 CFR 220.39 - Continuous radio monitoring.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Continuous radio monitoring. 220.39 Section 220.39..., DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.39 Continuous radio monitoring. Each radio used in a railroad operation shall be turned on to the...

  17. 76 FR 67397 - Radio Broadcasting Services; Llano, Texas

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-01

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Llano, Texas AGENCY: Federal Communications Commission... 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant... Communications Commission proposes to amend 47 CFR part 73 as follows: PART 73--RADIO BROADCAST SERVICES 1....

  18. 49 CFR 220.31 - Initiating a radio transmission.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Initiating a radio transmission. 220.31 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.31 Initiating a radio transmission. Before transmitting by radio, an employee shall: (a) Listen...

  19. 75 FR 71044 - Radio Broadcasting Services; Onekama, MI

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-22

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Onekama, MI AGENCY: Federal Communications Commission. ACTION: Final rule. SUMMARY: The Audio Division, at the request of Northern Radio of Michigan, Inc., in... CFR Part 73 Radio, Radio broadcasting. 0 For the reasons discussed in the preamble, the...

  20. Graphene electrostatic microphone and ultrasonic radio.

    PubMed

    Zhou, Qin; Zheng, Jinglin; Onishi, Seita; Crommie, M F; Zettl, Alex K

    2015-07-21

    We present a graphene-based wideband microphone and a related ultrasonic radio that can be used for wireless communication. It is shown that graphene-based acoustic transmitters and receivers have a wide bandwidth, from the audible region (20∼20 kHz) to the ultrasonic region (20 kHz to at least 0.5 MHz). Using the graphene-based components, we demonstrate efficient high-fidelity information transmission using an ultrasonic band centered at 0.3 MHz. The graphene-based microphone is also shown to be capable of directly receiving ultrasound signals generated by bats in the field, and the ultrasonic radio, coupled to electromagnetic (EM) radio, is shown to function as a high-accuracy rangefinder. The ultrasonic radio could serve as a useful addition to wireless communication technology where the propagation of EM waves is difficult. PMID:26150483

  1. The World of Radio Astronomy, Part 3

    NASA Astrophysics Data System (ADS)

    Dahlem, Michael; Brinks, Elias

    1996-07-01

    Street lamps are like quasars. Lightning bolts are like the Orion nebula. In addition to showing how celestial phenomenon resemble everyday doodads, radio astronomers are answering an age-old question: Where are we in the universe?

  2. Coordinated observations of PHEMU at radio wavelengths.

    NASA Astrophysics Data System (ADS)

    Pluchino, S.; Schillirò, F.; Salerno, E.; Pupillo, G.; Kraus, A.; Mack, K.-H.

    We present preliminary results for our study of mutual phenomena of the Galilean satellites performed at radio wavelengths with the Medicina and Noto antennas of the Istituto di Radioastronomia \\textendash{} INAF, and with the Effelsberg 100-m radio telescope of the Max-Planck-Institute for Radioastronomy. Measurements of the radio flux density variation occurred during the mutual occultations of Io by Europa and Ganymede were carried out during the PHEMU09 campaign at K- and Q-band. Flux density variations observed for the first time at radio wavelengths are consistent with the typical optical patterns measured when partial occultations occurred. The flux density drops indicate a non-linear dependence with the percentage of overlapped area.

  3. Need a Classroom Stimulus? Introduce Radio Astronomy

    NASA Astrophysics Data System (ADS)

    Derman, Samuel

    2010-04-01

    Silently, invisibly, ceaselessly, our planet Earth is showered by radio waves from every direction and from every region of space. This radio energy originates in our solar system, throughout the Milky Way galaxy, and far beyond, out to the remotest reaches of the universe. Detecting and unraveling the origins of these invisible signals is what radio astronomy is all about. This ever-present radiation provides astronomers with an alternate, non-optical window to the universe, revealing exotic and unfamiliar phenomena previously undetected by even the most powerful optical telescopes. For physics teachers, a classroom discussion of these radio discoveries, however brief, offers an opportunity for igniting interest (and possibly a career option) in even the most apathetic of students. This paper describes, first, the background of some of these events, and second (in the appendixes), a selection of numerical problems so that students can derive for themselves the truly mind-stretching features of these celestial objects.

  4. Two-Way Radio for Extension

    ERIC Educational Resources Information Center

    Swoboda, Donald W.

    1970-01-01

    Nebraska has been developing a two-way radio communication system for the Cooperative Extension Service, using the master microwave towers of the statewide emergency communication network. It has increased the efficiency of their limited human and economic resources. (NL)

  5. Graphene electrostatic microphone and ultrasonic radio

    PubMed Central

    Zhou, Qin; Zheng, Jinglin; Onishi, Seita; Crommie, M. F.; Zettl, Alex K.

    2015-01-01

    We present a graphene-based wideband microphone and a related ultrasonic radio that can be used for wireless communication. It is shown that graphene-based acoustic transmitters and receivers have a wide bandwidth, from the audible region (20∼20 kHz) to the ultrasonic region (20 kHz to at least 0.5 MHz). Using the graphene-based components, we demonstrate efficient high-fidelity information transmission using an ultrasonic band centered at 0.3 MHz. The graphene-based microphone is also shown to be capable of directly receiving ultrasound signals generated by bats in the field, and the ultrasonic radio, coupled to electromagnetic (EM) radio, is shown to function as a high-accuracy rangefinder. The ultrasonic radio could serve as a useful addition to wireless communication technology where the propagation of EM waves is difficult. PMID:26150483

  6. Forty Years of Radio Astronomy at Hartebeesthoek

    NASA Astrophysics Data System (ADS)

    Gaylard, M. J.; Nicolson, G. D.

    2007-07-01

    In 1961 an 85-foot (26-metre) diameter radio antenna was erected at Hartebeesthoek near Johannesburg, as NASA's Deep Space Instrumentation Facility 51. A young South African engineer employed there soon initiated a radio astronomy research programme to use free time between tracking spacecraft. On the closure of the facility by NASA in 1974, it was re-constituted as a radio astronomy observatory operated by the CSIR. In this paper, we highlight various strands of the forty year history of radio astronomy at Hartebeesthoek. We also cover some of the perhaps surprising spinoffs that it has generated, both scientifically and practically. Some of these hark back to measurements taken by the Abbé de la Caille at the Cape in the 1750's, and to the reasons for establishing a Royal Observatory there in the 1820's.

  7. The quest for short GRB radio afterglows

    NASA Astrophysics Data System (ADS)

    Burlon, Davide; Gaensler, Bryan; Murphy, Tara; Hancock, Paul; Bell, Martin; Bannister, Keith; Greiner, Jochen; Klose, Sylvio; Ghirlanda, Giancarlo

    2014-10-01

    Short γ-ray bursts (SGRBs) are the most elusive among GRBs with just a few of them having being studied pan- chromatically. Only three SGRBs have been detected in the radio band in the last 14 years. Radio observations of short GRBs should provide fundamental parameters of the physical process acting in these sources and on the nature of their progenitors. The detection of even a few more short GRBs in the radio band could constrain their true energetics, their radiative efficiency and the density of the environment where they happen (with immediate implications on the nature of their progenitors). The proposed joint radio-optical observations, will allow us for the first time to probe the hydrodynamics of the explosion and the radiation mechanism. We were graded 3.8 for two semesters, but the NAPA was not triggered.

  8. Coherent emission in fast radio bursts

    NASA Astrophysics Data System (ADS)

    Katz, J. I.

    2014-05-01

    The fast (ms) radio bursts reported by Lorimer et al. Science 318, 777 (2007) and Thornton et al. Science 341, 53 (2013) have extremely high brightness temperatures if at the inferred cosmological distances. This implies coherent emission by "bunches" of charges. Fast radio bursts, like the giant pulses of the Crab pulsar, display banded spectra that may be harmonics of plasma frequency emission by plasma turbulence and are inconsistent with emission by charge distributions moving relativistically. We model the emission region as a screen of half-wave dipole radiators resonant around the frequencies of observation, the maximally bright emission mechanism of nonrelativistic charges, and calculate the implied charge bunching. From this we infer the minimum electron energy required to overcome electrostatic repulsion. If fast radio bursts are the counterparts of Galactic events, their Galactic counterparts may be detected from any direction above the horizon by radio telescopes in their far sidelobes or by small arrays of dipoles.

  9. Radio wave propagation and acoustic sounding

    NASA Astrophysics Data System (ADS)

    Singal, S. P.

    Radio wave propagation of the decimetric and centimetric waves depends to a large extent on the boundary layer meteorological conditions which give rise to severe fadings, very often due to multipath propagation. Sodar is one of the inexpensive remote sensing techniques which can be employed to probe the boundary layer structure. In the paper a historical perspective has been given of the simultaneously conducted studies on radio waves and sodar at various places. The radio meteorological information needed for propagation studies has been clearly spelt out and conditions of a ray path especially in the presence of a ducting layer have been defined as giving rise to fading or signal enhancement conditions. Finally the potential of the sodar studies to obtain information about the boundary layer phenomena has been stressed, clearly spelling out the use of acoustic sounding in radio wave propagation studies.

  10. Gamma-Rays from Radio Galaxies

    NASA Astrophysics Data System (ADS)

    Madejski, Greg

    2016-07-01

    In this presentation, I will overview the properties of radio galaxies gleaned from observations of their gamma-ray emission, including that arising from the nuclear, and extended components. The gamma-ray spectra of radio galaxies measured by the Fermi-LAT and ground based Air Cerenkov telescopes will be considered in the context of their broad-band emission. The presentation will cover the most compelling models for emission processes, and will attempt to constrain the location of the nuclear gamma-ray emission. This will be compared to the observational properties of blazars, which are believed to be radio galaxies with jets pointing along our line of sight. Finally, I will discuss our best estimates for the contribution of unresolved radio galaxies to the diffuse gamma-ray emission.

  11. Goldstone Apple Valley Radio Telescope Project.

    ERIC Educational Resources Information Center

    Ibe, Mary; MacLaren, Dave

    2003-01-01

    Describes the Goldstone Apple Valley Radio Telescope (GAVRT) project as a way of teaching astronomy concepts to middle school students. The project provides students opportunities to work with professional scientists. (SOE)

  12. Radio Observations of SN 2008ha

    NASA Astrophysics Data System (ADS)

    Soderberg, Alicia

    2009-03-01

    I observed the peculiar SN 2008ha (CBET #1567) with the Very Large Array on 2008 Nov 21.99 UT at a frequency of 8.46 GHz. No radio source is detected at the optical SN position to a limit of 93 microJy (3 sigma). At a distance of 21 Mpc, this corresponds to a radio luminosity limit similar to those of nearby Type Ia supernovae (Panagia et al. 2006). It is also consistent with the observed radio luminosities for the nearest Type Ibc supernovae (e.g., SN 2002ap; Berger, Kulkarni & Chevalier 2002), but a factor of 10^3 and 10^5 below the radio luminosities of sub-energetic GRBs (Soderberg et al.

  13. Short range radio locator system

    DOEpatents

    McEwan, T.E.

    1996-12-31

    A radio location system comprises a wireless transmitter that outputs two megahertz period bursts of two gigahertz radar carrier signals. A receiver system determines the position of the transmitter by the relative arrival of the radar bursts at several component receivers set up to have a favorable geometry and each one having a known location. One receiver provides a synchronizing gating pulse to itself and all the other receivers. The rate of the synchronizing gating pulse is slightly offset from the rate of the radar bursts themselves, so that each sample collects one finely-detailed piece of information about the time-of-flight of the radar pulse to each receiver each pulse period. Thousands of sequential pulse periods provide corresponding thousand of pieces of information about the time-of-flight of the radar pulse to each receiver, in expanded, not real time. Therefore the signal processing can be done with relatively low-frequency, inexpensive components. A conventional microcomputer is then used to find the position of the transmitter by geometric triangulation based on the relative time-of-flight information. 5 figs.

  14. Integrally formed radio frequency quadrupole

    DOEpatents

    Abbott, Steven R.

    1989-01-01

    An improved radio frequency quadrupole (10) is provided having an elongate housing (11) with an elongate central axis (12) and top, bottom and two side walls (13a-d) symmetrically disposed about the axis, and vanes (14a-d) formed integrally with the walls (13a-d), the vanes (14a-d) each having a cross-section at right angles to the central axis (12) which tapers inwardly toward the axis to form electrode tips (15a-d) spaced from each other by predetermined distances. Each of the four walls (13a-d), and the vanes (14a-d) integral therewith, is a separate structural element having a central lengthwise plane (16) passing through the tip of the vane, the walls (13a-d) having flat mounting surfaces (17, 18) at right angles to and parallel to the control plane (16), respectively, which are butted together to position the walls and vane tips relative to each other.

  15. Short range radio locator system

    DOEpatents

    McEwan, Thomas E.

    1996-01-01

    A radio location system comprises a wireless transmitter that outputs two megahertz period bursts of two gigahertz radar carrier signals. A receiver system determines the position of the transmitter by the relative arrival of the radar bursts at several component receivers set up to have a favorable geometry and each one having a known location. One receiver provides a synchronizing gating pulse to itself and all the other receivers to sample the ether for the radar pulse. The rate of the synchronizing gating pulse is slightly offset from the rate of the radar bursts themselves, so that each sample collects one finely-detailed piece of information about the time-of-flight of the radar pulse to each receiver each pulse period. Thousands of sequential pulse periods provide corresponding thousand of pieces of information about the time-of-flight of the radar pulse to each receiver, in expanded, not real time. Therefore the signal processing can be done with relatively low-frequency, inexpensive components. A conventional microcomputer is then used to find the position of the transmitter by geometric triangulation based on the relative time-of-flight information.

  16. Radio frequency sustained ion energy

    DOEpatents

    Jassby, Daniel L.; Hooke, William M.

    1977-01-01

    Electromagnetic (E.M.) energy injection method and apparatus for producing and sustaining suprathermal ordered ions in a neutral, two-ion-species, toroidal, bulk equilibrium plasma. More particularly, the ions are produced and sustained in an ordered suprathermal state of existence above the average energy and velocity of the bulk equilibrium plasma by resonant rf energy injection in resonance with the natural frequency of one of the ion species. In one embodiment, the electromagnetic energy is injected to clamp the energy and velocity of one of the ion species so that the ion energy is increased, sustained, prolonged and continued in a suprathermal ordered state of existence containing appreciable stored energy that counteracts the slowing down effects of the bulk equilibrium plasma drag. Thus, selective deuteron absorption may be used for ion-tail creation by radio-frequency excitation alone. Also, the rf can be used to increase the fusion output of a two-component neutral injected plasma by selective heating of the injected deuterons.

  17. Phenomenology of Neptune's radio emissions observed by the Voyager planetary radio astronomy experiment

    NASA Technical Reports Server (NTRS)

    Pedersen, B. M.; Lecacheux, A.; Zarka, P.; Aubier, M. G.; Kaiser, M. L.; Desch, M. D.

    1992-01-01

    The Neptune flyby in 1989 added a new planet to the known number of magnetized planets generating nonthermal radio emissions. We review the Neptunian radio emission morphology as observed by the planetary radio astronomy experiment on board Voyager 2 during a few weeks before and after closest approach. We present the characteristics of the two observed recurrent main components of the Neptunian kilometric radiation, i.e., the 'smooth' and the 'bursty' emissions, and we describe the many specific features of the radio spectrum during closest approach.

  18. Evolution of luminous IRAS galaxies: Radio imaging

    NASA Technical Reports Server (NTRS)

    Neff, S. G.; Hutchings, J. B.

    1993-01-01

    In a recent study of IRAS galaxies' optical morphologies, we found that luminous IR sources lie in the IR color-luminosity plane in groups which separate out by optical spectroscopic type and also by degree of tidal disturbance. We found that the most luminous steep-IR-spectrum sources are generally galaxies in the initial stages of a major tidal interaction. Galaxies with active nuclei were generally found to have flatter IR spectra, to cover a range of IR luminosity, and to be in the later stages of a tidal interaction. We proposed a sequence of events by which luminous IR sources evolve: they start as interacting or merging galaxies, some develop active nuclei, and most undergo extensive star-formation in their central regions. Another way to study these objects and their individual evolution is to study their radio morphologies. Radio emission may arise at a detectable level from supernovae in star-forming regions and/or the appearance of an active nucleus can be accompanied by a nuclear radio source (which may develop extended structure). Therefore, the compact radio structure may trace the evolution of the inner regions of IRAS-luminous sources. If the radio sources are triggered by the interactions, we would expect to find the radio morphology related to the optical 'interactivity' of the systems. Here, we explore using the radio emission of IRAS galaxies as a possible tracer of galaxy evolution. We present and discuss observations of the compact radio morphology of 111 luminous IRAS-selected active galaxies covering a wide range of IR and optical properties.

  19. Big Data Challenges for Large Radio Arrays

    NASA Technical Reports Server (NTRS)

    Jones, Dayton L.; Wagstaff, Kiri; Thompson, David; D'Addario, Larry; Navarro, Robert; Mattmann, Chris; Majid, Walid; Lazio, Joseph; Preston, Robert; Rebbapragada, Umaa

    2012-01-01

    Future large radio astronomy arrays, particularly the Square Kilometre Array (SKA), will be able to generate data at rates far higher than can be analyzed or stored affordably with current practices. This is, by definition, a "big data" problem, and requires an end-to-end solution if future radio arrays are to reach their full scientific potential. Similar data processing, transport, storage, and management challenges face next-generation facilities in many other fields.

  20. Solar system radio astronomy at low frequencies

    NASA Technical Reports Server (NTRS)

    Desch, M. D.

    1987-01-01

    The planetary radio-astronomy observations obtained with the two Voyager spacecraft since their launch in 1977 are briefly characterized and illustrated with graphs, diagrams, and sample spectra. Topics addressed include the spacecraft designs and trajectories, the wavelength coverage of the radio instruments, the Io-controlled LF emission of Jupiter, the solar-wind effect on the Saturn kilometric radiation, the Saturn electrostatic discharges, and the use of the clocklike feature of the Uranus emission to measure the planet's rotation period.

  1. Radio Detection of Type Ib SNF20061011

    NASA Astrophysics Data System (ADS)

    Soderberg, Alicia

    2006-10-01

    "I observed the Type Ib SNF20061011 (ATEL 918) with the Very Large Array on Oct 23.1 UT as part of an ongoing program to study the radio properties of Type Ibc supernovae discovered through the SNF and SDSS search campaigns. The SN is clearly detected at 4.9 and 8.5 GHz with a radio luminosity of about 10^27 erg/cm^2/s/Hz. Further observations are planned.

  2. Non-thermal radio emission from Saturn

    NASA Technical Reports Server (NTRS)

    Warwick, J. W.

    1978-01-01

    Direct, strong evidence for non-thermal radio emission from Saturn exists in the hectometric data observed by Imp 6. The planet has been tentatively identified as a decametric source, but the most sensitive and most recent data fail to confirm this. At metric or decimetric wavelengths Saturn has no non-thermal emission like Jupiter's synchrotron sources. Finally, a comparative study of Earth and Jupiter radio emissions suggests lightning discharges.

  3. Magnetohydrodynamic solitons and radio knots in jets

    NASA Technical Reports Server (NTRS)

    Fiedler, R.

    1986-01-01

    Weakly nonlinear surface waves are examined in the context of the beam model for jetlike radio sources. By introducing a finite scale length, viz. the beam radius, geometrical dispersion can act to balance nonlinear wave growth and thereby produce solitons, localized wave packets of stable waveform. A method for obtaining a soliton equation from the MHD equations is presented and then applied to radio knots in jets.

  4. Voyager-Jupiter radio science data papers

    NASA Technical Reports Server (NTRS)

    Levy, G. S.; Wood, G. E.

    1980-01-01

    The reduction and interpretation of the radio science data from the Voyager 1 and 2 encounters of the planet Jupiter and its satellites resulted in the preparation of several papers for publication in the special Voyager-Jupiter issue of the Journal of Geophysical Research. The radio science and tracking systems of the Deep Space Network provide the data which makes this research possible. This article lists submitted papers by title, with their authors and with abstracts of their contents.

  5. NASA's SDR Standard: Space Telecommunications Radio System

    NASA Technical Reports Server (NTRS)

    Reinhart, Richard C.; Johnson, Sandra K.

    2007-01-01

    A software defined radio (SDR) architecture used in space-based platforms proposes to standardize certain aspects of radio development such as interface definitions, functional control and execution, and application software and firmware development. NASA has charted a team to develop an open software defined radio hardware and software architecture to support NASA missions and determine the viability of an Agency-wide Standard. A draft concept of the proposed standard has been released and discussed among organizations in the SDR community. Appropriate leveraging of the JTRS SCA, OMG s SWRadio Architecture and other aspects are considered. A standard radio architecture offers potential value by employing common waveform software instantiation, operation, testing and software maintenance. While software defined radios offer greater flexibility, they also poses challenges to the radio development for the space environment in terms of size, mass and power consumption and available technology. An SDR architecture for space must recognize and address the constraints of space flight hardware, and systems along with flight heritage and culture. NASA is actively participating in the development of technology and standards related to software defined radios. As NASA considers a standard radio architecture for space communications, input and coordination from government agencies, the industry, academia, and standards bodies is key to a successful architecture. The unique aspects of space require thorough investigation of relevant terrestrial technologies properly adapted to space. The talk will describe NASA s current effort to investigate SDR applications to space missions and a brief overview of a candidate architecture under consideration for space based platforms.

  6. Nonthermal Radio Emission and the HR Diagram

    NASA Technical Reports Server (NTRS)

    Gibson, D. M.

    1985-01-01

    Perhaps the most reliable indicator of non-radiative heating/momentum in a stellar atmosphere is the presence of nonthermal radio emission. To date, 77 normal stellar objects have been detected and identified as nonthermal sources. These stellar objects are tabulated herein. It is apparent that non-thermal radio emission is not ubiquitous across the HR diagram. This is clearly the case for the single stars; it is not as clear for the binaries unless the radio emission is associated with their late-type components. Choosing to make this association, the single stars and the late-type components are plotted together. The following picture emerges: (1) there are four locations on the HR diagram where non-thermal radio stars are found; (2) the peak incoherent 5 GHz luminosities show a suprisingly small range for stars within each class; (3) the fraction of stellar energy that escapes as radio emission can be estimated by comparing the integrated maximum radio luminosity to the bolometric luminosity; (4) there are no apparent differences in L sub R between binaries with two cool components, binaries with one hot and one cool component, and single stars for classes C and D; and (5) The late-type stars (classes B, C, and D) are located in parts of the HR diagram where there is reason to suspect that the surfaces of the stars are being braked with respect to their interiors.

  7. Enhancing GLAST Science Through Complementary Radio Observations

    NASA Astrophysics Data System (ADS)

    Ulvestad, James S.

    2006-12-01

    Radio astronomical observations with state-of-the-art instrumentation will be critical for achieving the maximum science return from the GLAST mission. Radio nterferometers with baselines of thousands of kilometers, such as the Very Long Baseline Array (VLBA), will provide sub-milliarcsecond imaging of GLAST blazars. High-frequency VLBA imaging, repeatable at intervals of days to weeks, will image the region where gamma-ray flares occur in blazars and help determine the location of the gamma-ray emission. Multi-frequency arcsecond-scale imaging with interferometers having baselines of one to tens of kilometers, particularly the Very Large Array, will provide efficient discrimination among the candidates for unidentified gamma-ray sources. Pulsar timing with single-dish radio telescopes such as the Green Bank Telescope will enable accurate registration of gamma-ray photons with pulsar ephemerides for studies of the pulsar emission mechanisms. Along with these contemporaneous radio/GLAST observing programs, we will discuss briefly some of the recent radio programs that have been conducted in preparation for GLAST launch. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

  8. Postwar Radio Astronomy and the US Military

    NASA Astrophysics Data System (ADS)

    Sullivan, W. T., III

    1993-12-01

    The course of radio astronomy in the United States during the period 1945-60 was greatly influenced by the funding and requirements of the US military. The scientific researchers and their military patrons continued the intimate relationship that had been so successful for the development of radar and communications during World War II. The result was a very high level of funding that led to large-scale projects, a concentration on the microwave portion of the radio spectrum, and primary interest in the sun, moon, and planets. These effects, however, ironically significantly contributed to the lag in US radio astronomy relative to that in Australia and England. Unlike the American approach, the strategy of the groups in Sydney, Cambridge and Jodrell Bank, reasoned that the most fruitful way to approach the radio sky at the time was with relatively simple equipment (largely revamped war surplus) operating at the lower frequencies. Other factors, such as the strength of optical astronomy in the US, also played important roles. By the mid-1960s, the microwave expertise that had been developed in the US finally paid off such that US radio astronomy was at last able to assume a position of more parity. Some similarities in the development of postwar Soviet radio astronomy will also be discussed.

  9. Radio Source Morphology: 'nature or nuture'?

    NASA Astrophysics Data System (ADS)

    Banfield, Julie; Emonts, Bjorn; O'Sullivan, Shane

    2012-10-01

    Radio sources, emanating from supermassive black-holes in the centres of active galaxies, display a large variety of morphological properties. It is a long-standing debate to what extent the differences between various types of radio sources are due to intrinsic properties of the central engine (`nature') or due to the properties of the interstellar medium that surrounds the central engine and host galaxy (`nurture'). Settling this `nature vs. nurture' debate for nearby radio galaxies, which can be studied in great detail, is vital for understanding the properties and evolution of radio galaxies throughout the Universe. We propose to observe the radio galaxy NGC 612 where previous observations have detected the presence of a large-scale HI bridge between the host galaxy and a nearby galaxy NGC 619. We request a total of 13 hrs in the 750m array-configuration to determine whether or not the 100 kpc-scale radio source morphology is directly related to the intergalactic distribution of neutral hydrogen gas.

  10. Spectral Indices of Faint Radio Sources

    NASA Astrophysics Data System (ADS)

    Gim, Hansung B.; Hales, Christopher A.; Momjian, Emmanuel; Yun, Min Su

    2015-01-01

    The significant improvement in bandwidth and the resultant sensitivity offered by the Karl G. Jansky Very Large Array (VLA) allows us to explore the faint radio source population. Through the study of the radio continuum we can explore the spectral indices of these radio sources. Robust radio spectral indices are needed for accurate k-corrections, for example in the study of the radio - far-infrared (FIR) correlation. We present an analysis of measuring spectral indices using two different approaches. In the first, we use the standard wideband imaging algorithm in the data reduction package CASA. In the second, we use a traditional approach of imaging narrower bandwidths to derive the spectral indices. For these, we simulated data to match the observing parameter space of the CHILES Con Pol survey (Hales et al. 2014). We investigate the accuracy and precision of spectral index measurements as a function of signal-to noise, and explore the requirements to reliably probe possible evolution of the radio-FIR correlation in CHILES Con Pol.

  11. Realistic Radio Communications in Pilot Simulator Training

    NASA Technical Reports Server (NTRS)

    Burki-Cohen, Judith; Kendra, Andrew J.; Kanki, Barbara G.; Lee, Alfred T.

    2000-01-01

    Simulators used for total training and evaluation of airline pilots must satisfy stringent criteria in order to assure their adequacy for training and checking maneuvers. Air traffic control and company radio communications simulation, however, may still be left to role-play by the already taxed instructor/evaluators in spite of their central importance in every aspect of the flight environment. The underlying premise of this research is that providing a realistic radio communications environment would increase safety by enhancing pilot training and evaluation. This report summarizes the first-year efforts of assessing the requirement and feasibility of simulating radio communications automatically. A review of the training and crew resource/task management literature showed both practical and theoretical support for the need for realistic radio communications simulation. A survey of 29 instructor/evaluators from 14 airlines revealed that radio communications are mainly role-played by the instructor/evaluators. This increases instructor/evaluators' own workload while unrealistically lowering pilot communications load compared to actual operations, with a concomitant loss in training/evaluation effectiveness. A technology review searching for an automated means of providing radio communications to and from aircraft with minimal human effort showed that while promising, the technology is still immature. Further research and the need for establishing a proof-of-concept are also discussed.

  12. The ultraviolet spectra of nearby radio galaxies

    NASA Technical Reports Server (NTRS)

    Keel, William C.; Windhorst, Rogier A.

    1991-01-01

    New and archival IUE SWP spectra are reported for nine nearby radio galaxies (V is less than 15 mag), together with optical emissionlike data for these galaxies as well as a number of candidates with weaker line emission. Both their UV line and continuum properties, as well as their UV and UV-optical line ratios, are examined. Ly-alpha emission is found to be common among local radio galaxies, at modest luminosities (typically 10 exp 41-42 erg/s). No apparent relation is found between L(Ly-alpha) and radio power for the nearby radio galaxies alone. The Ly-alpha/H-alpha ratio in low power nearby radio galaxies is 2-5 times lower than the prediction for case B recombination. The destruction of Ly-alpha photons by grains during resonant scattering can explain the observed deficiency for reasonable metallicities. The nearby radio galaxies have in general a small C IV/Ly-alpha ratio (less than 0.1). Comparison of the C IV and Ly-alpha strengths with those in luminous AGN suggests that most of the UV continuum comes from the stellar population, and not from the AGN.

  13. Radio properties of extragalactic IRAS sources

    NASA Technical Reports Server (NTRS)

    Condon, J. J.; Broderick, J. J.

    1991-01-01

    The present study identifies extragalactic sources from the IRAS Faint Source Catalog by position coincidence with radio sources stronger than 25 mJy and lying north of +5 deg on the Green Bank 4.85 GHz sky maps. Published VLA maps, new 4.86 GHz VLA maps made with 15-arcsec resolution, and accurate optical positions are used to confirm 122 of these candidate identifications. Normal and starburst spiral galaxies were found to comprise about 97 percent of the FIR flux-limited sample. Radio-loud 'monsters' with q less than 2.25 dominate the radio emission from about 2 percent of the FIR source sample, and radio-quiet monsters are responsible for the FIR emission from less than about 1 percent of the FIR sample. All of the radio-identified sources are optically identified, mostly with relatively bright nearby galaxies. No evidence was found for any new populations of high-redshift FIR sources, nonthermal sources with steep FIR/optical spectra, or dust-shrouded sources visible only at FIR and radio wavelengths.

  14. Brightest cluster galaxies in the extended GMRT radio halo cluster sample. Radio properties and cluster dynamics

    NASA Astrophysics Data System (ADS)

    Kale, R.; Venturi, T.; Cassano, R.; Giacintucci, S.; Bardelli, S.; Dallacasa, D.; Zucca, E.

    2015-09-01

    Aims: First-ranked galaxies in clusters, usually referred to as brightest cluster galaxies (BCGs), show exceptional properties over the whole electromagnetic spectrum. They are the most massive elliptical galaxies and show the highest probability to be radio loud. Moreover, their special location at the centres of galaxy clusters raises the question of the role of the environment in shaping their radio properties. In the attempt to separate the effect of the galaxy mass and of the environment on their statistical radio properties, we investigate the possible dependence of the occurrence of radio loudness and of the fractional radio luminosity function on the dynamical state of the hosting cluster. Methods: We studied the radio properties of the BCGs in the Extended GMRT Radio Halo Survey (EGRHS), which consists of 65 clusters in the redshift range 0.2-0.4, with X-ray luminosity LX ≥ 5 × 1044 erg s-1, and quantitative information on their dynamical state from high-quality Chandra imaging. We obtained a statistical sample of 59 BCGs, which we divided into two classes, depending on whether the dynamical state of the host cluster was merging (M) or relaxed (R). Results: Of the 59 BCGs, 28 are radio loud and 31 are radio quiet. The radio-loud sources are favourably located in relaxed clusters (71%), while the reverse is true for the radio-quiet BCGs, which are mostly located in merging systems (81%). The fractional radio luminosity function for the BCGs in merging and relaxed clusters is different, and it is considerably higher for BCGs in relaxed clusters, where the total fraction of radio loudness reaches almost 90%, to be compared to the ~30% in merging clusters. For relaxed clusters, we found a positive correlation between the radio power of the BCGs and the strength of the cool core, consistent with previous studies on local samples. Conclusions: Our study suggests that the radio loudness of the BCGs strongly depends on the cluster dynamics; their fraction is

  15. Sensitive radio survey of obscured quasar candidates

    NASA Astrophysics Data System (ADS)

    Alexandroff, Rachael M.; Zakamska, Nadia L.; van Velzen, Sjoert; Greene, Jenny E.; Strauss, Michael A.

    2016-08-01

    We study the radio properties of moderately obscured quasars in samples at both low (z ˜ 0.5) and high (z ˜ 2.5) redshift to understand the role of radio activity in accretion, using the Karl G. Jansky Very Large Array (VLA) at 6.0GHz and 1.4GHz. Our z ˜ 2.5 sample consists of optically-selected obscured quasar candidates, all of which are radio-quiet, with typical radio luminosities of νLν[1.4 GHz]⪉ 10^{40} erg s-1. Only a single source is individually detected in our deep (rms˜10 μJy) exposures. This population would not be identified by radio-based selection methods used for distinguishing dusty star-forming galaxies and obscured active nuclei. In our pilot A-array study of z ˜ 0.5 radio-quiet quasars, we spatially resolve four of five objects on scales ˜5 kpc and find they have steep spectral indices with an average value of α = -0.75. Therefore, radio emission in these sources could be due to jet-driven or radiatively driven bubbles interacting with interstellar material on the scale of the host galaxy. Finally, we also study the additional population of ˜200 faint (˜40μJy - 40mJy) field radio sources observed over ˜120 arcmin2 of our data. 60% of these detections (excluding our original targets) are matched in the Sloan Digital Sky Survey (SDSS) and/or Wide-Field Infrared Survey Explorer (WISE) and are, in roughly equal shares, active galactic nuclei (AGN) at a broad range of redshifts, passive galaxies with no other signs of nuclear activity and infrared-bright but optically faint sources. Spectroscopically or photometrically confirmed star-forming galaxies constitute only a small minority of the matches. Such sensitive radio surveys allow us to address important questions of AGN evolution and evaluate the AGN contribution to the radio-quiet sky.

  16. Wideband Observations of Radio Pulsars

    NASA Astrophysics Data System (ADS)

    Pennucci, Timothy T.

    2015-08-01

    Pulsars are exotic objects which have yielded a bounty of important astrophysical results. As rapidly rotating, highly magnetized neutron stars, pulsars' stable rotation and beamed radio emission enables their use as interstellar laboratory clocks. The extraordinary timing regularity of the millisecond pulsar (MSP) population permits some of the most precise measurements in astronomy. The discovery of MSPs raised the probability of directly detecting gravitational waves for the first time. Ongoing efforts by several pulsar timing array (PTA) collaborations compliment the ground- and space-based efforts of laser interferometers. One such PTA is the North American Nanohertz Observatory for Gravitational Waves (NANOGrav). NANOGrav has recently employed a new set of wideband instruments to increase the sensitivity of their PTA, and the future of pulsar astronomy is moving towards progressively larger bandwidths. In this dissertation, we address the benefits and issues from adopting the new instrumentation, particularly for the scientific motivations of NANOGrav. We first develop a measurement technique for simultaneously obtaining pulse times-of-arrival (TOAs) and dispersion measures (DMs) using 2D models of evolving Gaussian components. We then apply the methodology broadly to a variety of pulsars, including a bright, test MSP in a globular cluster, the Galactic Center magnetar, and the entire suite of 37 MSPs from the NANOGrav 9-year data set. For a subset of these MSPs, we make targeted observations at specific orbital phases aimed at improving the timing models and constraining the Shapiro delay. With a few exceptions, we find positive or consistent timing results from the implementation of our first generation wideband timing protocol. Some highlights include: improved measurement uncertainties, mitigation of chromatic ISM effects, a reduction in the number of timing parameters and TOAs, signs of chromatic DMs, and at least one new pulsar mass.

  17. Determinación de elementos orbitales del Cometa C/1995 O1 (Hale-Bopp)

    NASA Astrophysics Data System (ADS)

    Carozza, J. R.; Mackintosh, R.

    Based on 98 astrometric positions (1995 August 20 - 1998 June 26) obtained from CCD images acquired and reduced by the Sección Sistema Solar of the AAAA Observatory, orbital elements for the comet C/1995 O1 (Hale-Bopp) were determinated. The resulting elements show a mean residual of 0.07" and a r.m.s. of 1.47".

  18. Compact Radio Sources in NGC 660

    NASA Astrophysics Data System (ADS)

    Wiercigroch, A. B.

    1995-12-01

    The nuclei of starburst galaxies are often obscured by dust and hence are probed best in non-visual wavelength regimes such as the infrared and radio. For example, radio studies of classical starburst galaxies such as NGC 253 and M82 have identified ~ 50 compact sources in each galaxy. One of the purposes of this type of observing program has been to classify the compact radio sources as H II regions or radio supernovae, and to estimate the supernova rates. If obtainable, spectral indices are used to identify the compact structures; otherwise supporting evidence or assumptions are needed. NGC 660, located at a distance of 7.5 Mpc, is a strong candidate for a search for compact radio sources. It is a relatively strong infrared emitter, has far infrared colors similar to NGC 253 and M82, and shows several peaks in published Very Large Array (VLA) maps at 6 cm and 20 cm. We therefore observed NGC 660 at 3.6 cm in the A-configuration of the VLA on 1995 July 13--14. Total integration time on-source was 4.8 hrs. The image shows a large family ( ~ 20) of compact radio structures with a flux density range of 0.1--3.4 mJy, three of which have fluxes > 2.0 mJy. The source luminosities are comparable to those of the stronger sources in M82 and NGC 253, typically a few times more powerful than Cas A. A number of the compact sources appear to lie along a ring projected against the more diffuse radio emission in the galaxy's nuclear region. The work described in this paper was carried out by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

  19. Curved Radio Spectra of Weak Cluster Shocks

    NASA Astrophysics Data System (ADS)

    Kang, Hyesung; Ryu, Dongsu

    2015-08-01

    In order to understand certain observed features of arc-like giant radio relics such as the rareness, uniform surface brightness, and curved integrated spectra, we explore a diffusive shock acceleration (DSA) model for radio relics in which a spherical shock impinges on a magnetized cloud containing fossil relativistic electrons. Toward this end, we perform DSA simulations of spherical shocks with the parameters relevant for the Sausage radio relic in cluster CIZA J2242.8+5301, and calculate the ensuing radio synchrotron emission from re-accelerated electrons. Three types of fossil electron populations are considered: a delta-function like population with the shock injection momentum, a power-law distribution, and a power law with an exponential cutoff. The surface brightness profile of the radio-emitting postshock region and the volume-integrated radio spectrum are calculated and compared with observations. We find that the observed width of the Sausage relic can be explained reasonably well by shocks with speed {u}{{s}}˜ 3× {10}3 {km} {{{s}}}-1 and sonic Mach number {M}{{s}}˜ 3. These shocks produce curved radio spectra that steepen gradually over (0.1-10){ν }{br} with a break frequency {ν }{br}˜ 1 GHz if the duration of electron acceleration is ˜60-80 Myr. However, the abrupt increase in the spectral index above ˜1.5 GHz observed in the Sausage relic seems to indicate that additional physical processes, other than radiative losses, operate for electrons with {γ }{{e}}≳ {10}4.

  20. Curved Radio Spectra of Weak Cluster Shocks

    NASA Astrophysics Data System (ADS)

    Kang, Hyesung; Ryu, Dongsu

    2015-08-01

    In order to understand certain observed features of arc-like giant radio relics such as the rareness, uniform surface brightness, and curved integrated spectra, we explore a diffusive shock acceleration (DSA) model for radio relics in which a spherical shock impinges on a magnetized cloud containing fossil relativistic electrons. Toward this end, we perform DSA simulations of spherical shocks with the parameters relevant for the Sausage radio relic in cluster CIZA J2242.8+5301, and calculate the ensuing radio synchrotron emission from re-accelerated electrons. Three types of fossil electron populations are considered: a delta-function like population with the shock injection momentum, a power-law distribution, and a power law with an exponential cutoff. The surface brightness profile of the radio-emitting postshock region and the volume-integrated radio spectrum are calculated and compared with observations. We find that the observed width of the Sausage relic can be explained reasonably well by shocks with speed {u}{{s}}∼ 3× {10}3 {km} {{{s}}}-1 and sonic Mach number {M}{{s}}∼ 3. These shocks produce curved radio spectra that steepen gradually over (0.1–10){ν }{br} with a break frequency {ν }{br}∼ 1 GHz if the duration of electron acceleration is ∼60–80 Myr. However, the abrupt increase in the spectral index above ∼1.5 GHz observed in the Sausage relic seems to indicate that additional physical processes, other than radiative losses, operate for electrons with {γ }{{e}}≳ {10}4.