scholarly journals Possible detection of a pulsar of decameter radio waves in the direction of the galactic center.

1989 ◽  
Vol 41 (4) ◽  
pp. 331-369
Author(s):  
Hiroshi OYA ◽  
Masahide IIZIMA ◽  
Akira MORIOKA
Keyword(s):  
Galactic Center ◽  
Radio Waves ◽  
Decameter Radio

scholarly journals NCREASING IMMUNITY OF DECAMETER RADIO CHANNEL TRANSMISSIONS UNDER UNINTENDED INTERFERENCE

T-Comm ◽  
2021 ◽  
Vol 15 (6) ◽  
pp. 4-9
Author(s):  
Sergey V. Dvornikov ◽  
◽  
Evgeniy V. Markov ◽  
Adjan A. Manoshi ◽  
◽  
...  
Keyword(s):  
Fading Channels ◽  
Rayleigh Fading ◽  
Noise Immunity ◽  
Radio Channel ◽  
Radio Waves ◽  
Radio Communication ◽  
Radio Channels ◽  
Shift Keying ◽  
Decameter Radio ◽  
Significant Length

The transmission of messages is a complex process, which is largely determined by the properties of the radio channel used. Decameter radio channels are the most difficult for organizing communication, since the ionospheric propagation of radio waves is associated with their significant attenuation, due to the significant length of the paths, as well as the presence of Rayleigh fading in the channel. However, the possibility of transmitting information over long distances without serious resource costs stimulates further research to improve the reliability of decameter radio communication. In this paper, we investigate the possibility of increasing the noise immunity of frequency-shift keying transmissions of decameter radio channels in conditions of unintentional interference due to the use of broadband signals. An analytical expression of the dependence of the probability of a bit error on the level of the ratio of the peak signal power to the peak interference power is considered; a graph of this dependence is presented. It is shown that the plot is consistent with the overall noise immunity estimate for Rayleigh fading channels using double FSK signals. The rationality of methods for obtaining the required reception quality in decameter radio channels is analyzed. It is shown that the most rational direction for increasing the noise immunity of FM-2 transmissions in decameter radio channels with Rayleigh fading in conditions of unintended interference is the use of broadband signals. In this case, for expansion, it is advisable to choose a value kf = 7, which makes it possible to increase the noise immunity by 9 dB. The conclusions are illustrated by graphs.

scholarly journals Forecasting characteristics of propagation of decameter radio waves using the global ionosphere and plasmasphere model

2015 ◽  
Vol 1 (3) ◽  
pp. 49-54 ◽  
Author(s):  
Сергей Пономарчук ◽  
Sergey Ponomarchuk ◽  
Галина Котович ◽  
Galina Kotovich ◽  
Елена Романова ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Radio Wave ◽  
Normal Wave ◽  
Middle Latitude ◽  
Radio Wave Propagation ◽  
Radio Waves ◽  
Radio Communication ◽  
Iri Model ◽  
Decameter Radio ◽  
Minimum Number

We present the forecast results of maximal usable frequencies for mid-latitude paths on the base of complex We present the results of forecasting maximum usable frequencies (MUF) on middle-latitude paths on the basis of complex algorithm including modules of the ionosphere and plasmasphere global model (IPGM) and the model of radio wave propagation. The computation of propagation characteristics for decameter radio waves is carried out within the framework of normal wave technique. IPGM developed in ISTP SB RAS enables to compute electron concentration profiles and effective frequency of collisions using minimum number of input data and taking into account physical processes in the Earth’s upper atmosphere. To estimate the efficiency of using IPGM in long-term forecast of radio wave propagation we computed MUF for radio communication in various heliogeophysical conditions. To obtain precision characteristics of MUF forecast we used experimental data of oblique sounding on Magadan–Irkutsk, Khabarovsk–Irkutsk, Norilsk–Irkutsk paths. The paths are equipped with modern ionosphere diagnostic hardware for oblique sounding by continuous chirp signal. We also compared results of MUF forecast using IPGM with computations carried out according IRI model.

Deviation of decameter radio waves from the great circle path at high latitudes

1991 ◽  
Vol 34 (2) ◽  
pp. 102-105
Author(s):  
N. F. Blagoveshchenskaya ◽  
A. N. Baranets ◽  
T. D. Borisova ◽  
V. A. Bubnov
Keyword(s):  
Great Circle ◽  
High Latitudes ◽  
Radio Waves ◽  
Decameter Radio ◽  
Great Circle Path

scholarly journals Interstellar Broadening of Compact Low Galactic Latitude Radio Sources

1984 ◽  
Vol 110 ◽  
pp. 309-312
Author(s):  
Brian Dennison ◽  
M. Thomas ◽  
J. J. Broderick ◽  
R. S. Booth ◽  
Robert L. Brown ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Radio Source ◽  
Electron Density ◽  
Galactic Center ◽  
Galactic Disk ◽  
Angular Diameter ◽  
Radio Sources ◽  
Galactic Latitude ◽  
Radio Waves

Scattering of radio waves off inhomogeneities in electron density in the interstellar medium can produce an apparent broadening in the angular diameter of an intrinsically compact background radio source. The magnitude and distribution of this effect at low galactic latitudes (|b|<5°) is not well known, although several cases suggest substantial broadening in certain directions, such as the Cygnus X region (Anderson et al. 1972), and the galactic center (Davies, Walsh, and Booth 1976). Large scattering in the plane is consistent with the scintillation properties of pulsars seen through substantial thicknesses (≳ 1 kpc) of the galactic disk.

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