scholarly journals Design and testing of a portable radio telescope for studying cosmic radiation in the frequency range 1300-1550 MHz.

2020 ◽  
Vol 2020 (7) ◽  
Author(s):  
A.S. Pochinok ◽  
Keyword(s):  
Radio Telescope ◽  
Cosmic Radiation ◽  
Frequency Range ◽  
Portable Radio ◽  
Design And Testing

scholarly journals The design and testing issues of radiation tolerant microwave amplifiers implemented in the domestic GaAs pHEMT 0.5 μm process

2019 ◽  
Vol 30 ◽  
pp. 10001
Author(s):  
Denis Sotskov ◽  
Alexander Kuznetsov ◽  
Nikolay Usachev ◽  
Vadim Elesin ◽  
Ilya Selishchev
Keyword(s):  
Radiation Effects ◽  
Noise Figure ◽  
Supply Voltage ◽  
Frequency Range ◽  
Microwave Amplifiers ◽  
Operating Frequency Range ◽  
Single Positive ◽  
Extended Frequency ◽  
Radiation Tolerant ◽  
Design And Testing

The investigation results of the possibility of manufacturing radiation tolerant microwave amplifiers implementing in domestic GaAs D-mode pHEMT 0.5 μm process are presented in this work. The amplifier with an operating frequency range from 0.1 GHz to 3.5 GHz, gain above 15 dB, noise figure below 2.2 dB, output linearity above 17 dBm is designed, produced and measured. The characteristic property of the amplifier is a single positive supply voltage and extended frequency range up to 100 MHz provided by the external capacitor circuit. Transient radiation effects in the amplifier are investigated up to the dose rate value of 4.9·109 a.u./s. The recovery time does not exceed 4 μs according to the experimental results.

scholarly journals Zebra pattern in decametric radio emission of Jupiter

2018 ◽  
Vol 610 ◽  
pp. A69 ◽  
Author(s):  
M. Panchenko ◽  
S. Rošker ◽  
H. O. Rucker ◽  
A. Brazhenko ◽  
P. Zarka ◽  
...  
Keyword(s):  
Radio Emission ◽  
Radio Telescope ◽  
Narrow Band ◽  
Central Meridian ◽  
Frequency Interval ◽  
Frequency Range ◽  
Systematic Analysis ◽  
Zebra Pattern ◽  
Left Handed ◽  
New Type

We report the systematic analysis of zebra-like fine spectral structures in decametric frequency range of Jovian radio emission. Observations were performed by the large ground-based radio telescope URAN-2 during three observation campaigns between, Sep., 2012, and May, 2015. In total, 51 zebra pattern (ZP) events were detected. These rare fine radio features are observed in frequency range from 12.5 to 29.7 MHz as quasi-harmonically related bands of enhanced brightness. ZPs are strongly polarized radio emission with a duration from 20 s to 290 s and flux densities ~105−106 Jy (normalized to 1 AU), that is, 1–2 orders lower than for Io-decametric radio emission (DAM). Occurrence of the events does not depend on the position of Io satellite but is strongly controlled by the Jovian central meridian longitude (CML). ZPs are mainly detected in two active sectors of Jovian CMLs: 100∘ to 160∘ for Northern sources (right-handed polarized) and 300∘ and 60∘ (via 360∘) for the Southern sources (left-handed). The frequency interval between neighboring stripes is from 0.26 to 1.5 MHz and in most cases this interval increases with frequency. We discussed the double plasma resonance with electrons or ions as a possible source of the ZPs. The performed analysis of the observations allows us to conclude that the observed ZPs are a new type of narrow band spectral structures in the Jovian DAM.

scholarly journals Measurements Of The Flux Density Of Discrete Radio Sources At 6 Cm Wavelength

1966 ◽  
Vol 19 (4) ◽  
pp. 577 ◽  
Keyword(s):  
Flux Density ◽  
Radio Telescope ◽  
Power Law ◽  
Radio Sources ◽  
Frequency Range ◽  
Thermal Radio ◽  
Discrete Radio Sources ◽  
Selection Of ◽  
Lower Frequencies

The flux densities of 67 non-thermal radio sources have been measured at a frequency of 5000 Mc/s with the CSIRO 210 ft radio telescope at Parkes. The sources were chosen from the stronger objects in the 3C catalogue (Edge et al. 1959), the CTA and CTD catalogues (Harris and Roberts 1960; Kellermann and Read 1965), and the Parkes catalogue (Bolton, Gardner, and Mackey 1964; Price and Milne 1965; Day et al. 1966). In the selection of sources observed in this program, special emphasis was placed on objects whose spectra at lower frequencies showed significant departures from the usual power law with an index near -0�8. Most of the sources reported here have not been previously measured at wavelengths shorter than 10 cm and thus the present observations extend the frequency range of their spectra by nearly a factor of two.

scholarly journals 21. The low-frequency spectrum of Cygnus A and Cassiopeia A

1957 ◽  
Vol 4 ◽  
pp. 145-147
Author(s):  
R. J. Lamden ◽  
A. C. B. Lovell
Keyword(s):  
Lower Limit ◽  
Radio Telescope ◽  
Low Frequency ◽  
Radio Sources ◽  
Pencil Beam ◽  
Frequency Range ◽  
Present Communication ◽  
Cassiopeia A ◽  
Cygnus A ◽  
Radio Transmitters

The published measurements of the intensity of the radio sources cover a frequency range down to a lower limit of 22·6 Mc./s., at which measurements have been made on Cygnus and Cassiopeia by Hey and Hughes (1954)[1]. Information about the spectrum at still lower frequencies is difficult to obtain because of interference arising from ionospheric reflexion of distant radio transmitters. Some of this trouble can be alleviated by using a narrow pencil-beam radio telescope for reception and the present communication describes measurements made on frequencies of 16·5, 19·0, 22·6 and 30·0 Mc./s. using the 218 ft. transit radio telescope at Jodrell Bank.

scholarly journals Design and Testing of a 3-DOF Robot for Studying the Human Response to Vibration

Machines ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 67
Author(s):  
Pietro Marzaroli ◽  
Alessandro Albanetti ◽  
Edoardo Negri ◽  
Hermes Giberti ◽  
Marco Tarabini
Keyword(s):  
Numerical Optimization ◽  
Vertical Direction ◽  
Human Response ◽  
Frequency Range ◽  
Quadratic Error ◽  
Testing Conditions ◽  
Multibody Dynamic ◽  
The Mean ◽  
Design And Testing

This work describes the design and validation of an electro-mechanical excitation system for characterization of the response of the human body to multiaxial vibrations. The presented system is based on the linear delta configuration and is designed to expose standing subjects to vibration along three perpendicular axes, with an excitation bandwidth of at least 30 Hz and a maximum vibration amplitude of ±30 mm along the vertical direction and ±20 mm along the horizontal directions. The shaker characteristic dimensions are the result of numerical optimization of the inverse manipulability index; the motors and transmissions have been selected using a multibody dynamic simulation. Finite element simulations were performed to ensure that the structural resonances were outside the excitation bandwidth. Once the shaker had been manufactured, experiments were performed to verify the capability of the system in real testing conditions. The mean quadratic error between the modulus of the imposed acceleration and the measured one is between 5.7 × 10−3 and 1.4 × 10−2 m/s2 in the frequency range between 1 and 50 Hz, proving the good outcome of the design process.

Spectral Polarimetric Observations of the Sun by the VIRAC RT-32 Radio Telescope: First Results

2013 ◽  
Vol 22 (1) ◽  
Author(s):  
D. Bezrukov
Keyword(s):  
Radio Telescope ◽  
Radio Astronomy ◽  
Microwave Emission ◽  
The Sun ◽  
Frequency Range ◽  
First Results

AbstractThe article describes microwave observations of the Sun with the radio telescope RT-32 of the Ventspils International Radio Astronomy Center. The observations were performed using a multichannel spectral polarimeter for the 6.3–9.4 GHz frequency range. A set of 2D microwave emission maps of the Sun for the Stokes I and V parameters has been obtained and analyzed.

scholarly journals MeerKAT and its potential for Cosmic MASER Research

2012 ◽  
Vol 8 (S287) ◽  
pp. 483-487
Author(s):  
Roy Booth ◽  
Sharmila Goedhart ◽  
Justin Jonas
Keyword(s):  
General Relativity ◽  
South African ◽  
Southern Hemisphere ◽  
Radio Telescope ◽  
World Wide ◽  
Frequency Range ◽  
Telescope Array ◽  
Band Frequency ◽  
Frequency Bands ◽  
Water Masers

AbstractThe MeerKAT radio telescope array is the South African precursor instrument for the proposed Square Kilometer Array's mid-band frequency range. It will be the most sensitive centimetre-wavelength telescope in the southern hemisphere until the SKA is built. It will cover a broad range of astronomical science from the evolution of galaxies to tests of Einstein's theory of General Relativity, using Pulsars. The chosen frequency bands will enable sensitive southern Galactic maser surveys in the main lines of hydroxyl, 12 GHz methanol and perhaps 14.5 GHz formaldehyde lines as well as searches for redshifted water masers from red-shifts greater than about 0.5. Proposals for Large Surveys using MeerKAT were solicited in late 2009 and resulted in some 20 proposals from teams comprising 500 scientists, world-wide. The successful proposals relevant to maser research will be discussed below.

scholarly journals RFI Survey for the Giant Metrewave Radio Telescope in India

1991 ◽  
Vol 112 ◽  
pp. 190-193
Author(s):  
G. Swarup ◽  
T.L. Venkatasubramani
Keyword(s):  
Radio Frequency ◽  
Radio Telescope ◽  
Radio Astronomy ◽  
Radio Frequency Interference ◽  
Frequency Range ◽  
Extragalactic Astronomy ◽  
Low Level ◽  
Highly Sensitive ◽  
Set Up

ABSTRACTA Giant Meterwave Radio Telescope (GMRT) is being set up at Khodad about 80 km north of Pune in India for operation in the frequency range of about 30 to 1500 MHz. It is to be completed by 1992 and is being designed to investigate many outstanding problems in the fields of galactic and extragalactic astronomy. We present here measurements of man-made radio frequency interference (RFI) conducted at the GMRT site in 1985 and 1988. It is seen that highly sensitive radio astronomy observations can still be made at selected bands in the above frequency range because of the relatively low level of RFI in India. However, this advantage may not remain for more than a decade or two.

scholarly journals Kilometer-Square Area Radio Synthesis Telescope Karst Project

1998 ◽  
Vol 179 ◽  
pp. 93-94
Author(s):  
B. Peng ◽  
R. Nan
Keyword(s):  
Radio Telescope ◽  
Southwest China ◽  
Radio Interference ◽  
Frequency Range ◽  
Large Radio Telescope ◽  
Spherical Reflector ◽  
Individual Unit ◽  
Project Site

One way to realize the Large radio Telescope with a collecting area approaching one square kilometer, continuously covering a frequency range between 200 MHz and 2 GHz, is to construct a passive spherical reflector array of about 30 individual unit telescopes, each ∼ 300 m diameter(Butcher 1995). Valleys amid the hills of southwest China would be ideal for such LT concept. We refer to this effort as the Kilometer-square Area Radio Synthesis Telescope project. Site surveying and Radio Interference monitoring looks promising. Engineering considerations are summarized.

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