The effect of stimulated combination scattering on two-quantum absorption in the radio-frequency range

1971 ◽  
Vol 14 (9) ◽  
pp. 1054-1057
Author(s):  
O. B. Anan'in ◽  
Yu. A. Bykovskii ◽  
�. A. Manykin ◽  
A. N. Petrovskii
Keyword(s):  
Radio Frequency ◽  
Frequency Range ◽  
Combination Scattering

Radio Observations of Two Large Solar Disturbances

1951 ◽  
Vol 4 (1) ◽  
pp. 51
Author(s):  
JV Hindman ◽  
AG Little ◽  
R Payne-Scott ◽  
DE Yabsley ◽  
CW Allen
Keyword(s):  
Radio Frequency ◽  
Solar Flares ◽  
Radio Frequency Power ◽  
Frequency Range ◽  
Power Flux ◽  
Apparent Position ◽  
Radio Receivers ◽  
Solar Origin ◽  
Solar Disturbances ◽  
Frequency Power

On February 17 and 21-22, 1950, two exceptionally large radio-frequency disturbances of solar origin were observed on seven radio receivers working in the frequency range from 62 to 9400 Mc/s. At each of the frequencies the radio-frequency power flux was recorded continuously during the disturbance and at several frequencies the polarization of the radiation was examined. The apparent position of the origin of the radiation was determined at one frequency. The time of commencement and the duration of the disturbances at the different frequencies were compared with each other and with those of associated phenomena, solar flares, radio fade-outs, and geomagnetic effects. The two disturbances show marked similarities and marked differences ; these are summarized.

scholarly journals Radio-frequency interference mitigating hyperspectral L-band radiometer

2017 ◽  
Vol 6 (1) ◽  
pp. 39-51 ◽  
Author(s):  
Peter Toose ◽  
Alexandre Roy ◽  
Frederick Solheim ◽  
Chris Derksen ◽  
Tom Watts ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Thermal Emission ◽  
Absolute Error ◽  
Radio Frequency Interference ◽  
Frequency Range ◽  
Passive Remote Sensing ◽  
Extended Frequency ◽  
L Band ◽  
Radiometric Signal ◽  
Microwave Radiometers

Abstract. Radio-frequency interference (RFI) can significantly contaminate the measured radiometric signal of current spaceborne L-band passive microwave radiometers. These spaceborne radiometers operate within the protected passive remote sensing and radio-astronomy frequency allocation of 1400–1427 MHz but nonetheless are still subjected to frequent RFI intrusions. We present a unique surface-based and airborne hyperspectral 385 channel, dual polarization, L-band Fourier transform, RFI-detecting radiometer designed with a frequency range from 1400 through  ≈  1550 MHz. The extended frequency range was intended to increase the likelihood of detecting adjacent RFI-free channels to increase the signal, and therefore the thermal resolution, of the radiometer instrument. The external instrument calibration uses three targets (sky, ambient, and warm), and validation from independent stability measurements shows a mean absolute error (MAE) of 1.0 K for ambient and warm targets and 1.5 K for sky. A simple but effective RFI removal method which exploits the large number of frequency channels is also described. This method separates the desired thermal emission from RFI intrusions and was evaluated with synthetic microwave spectra generated using a Monte Carlo approach and validated with surface-based and airborne experimental measurements.

LIGHT AND SECURE COMMUNICATION ALGORITHM FOR COGNITIVE RADIO NETWORK BY USING LABYRINTHINE AUTHENTICATION FORMULA

2015 ◽  
Vol 76 (1) ◽  
Author(s):  
Fawad Salam Khan ◽  
Talha Naqash ◽  
Muhammad Ibrar Khatak ◽  
Raja Masood Larik
Keyword(s):  
Cognitive Radio ◽  
Radio Frequency ◽  
Communication System ◽  
Secure Communication ◽  
Cognitive Radio Network ◽  
Transmission Capacity ◽  
Effective Range ◽  
Radio Network ◽  
Frequency Range ◽  
Day By Day

Facilities for different sight and sound provisions in remote systems requests extra transmission capacity in the radio frequency range. Effective range administration calculations are important to accomplish massive accomplishment in remote correspondences. Usage of licensed spectrum is increasing day by day so Cognitive Radio is proposed as a solution to meet the demands. CR is a symbolization procedure that distributes the authorized range (the licensed spectrum) despite the fact that facing least obstruction to the authorized clients. In this paper, we investigate the versatile qualities of cognitive radio in secure and dependable correspondence. Anyway the inquiry is the way to make the correspondence dependable such that there happens no spying and data spillage. The conceivable results incorporate coordinating the benefits of spread range balance, utilizing encryption calculations (Encryption keys), and its possibility to switch over different recurrence groups. We concentrate on the different requisitions of CR and the various philosophies which empower a safe Communication system. 

scholarly journals Surveying RFI for a new Brazilian Solar Spectroscope site

2009 ◽  
Vol 5 (S264) ◽  
pp. 484-486
Author(s):  
José R. Cecatto ◽  
Paulo C. G. Albuquerque ◽  
Ivan O. G. Vila ◽  
Alan B. Cassiano ◽  
César Strauss ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Daily Basis ◽  
High Time ◽  
Radio Frequency Interference ◽  
Frequency Range ◽  
Site Change ◽  
The Moment ◽  
Antenna Location

AbstractBrazilian Solar Spectroscope (BSS) carry out high time (0.01–0.1 s) resolution solar spectral investigations within the frequency range 1–2.5 GHz on a daily basis. At the moment, a new site is imposed to this facility. This site change became necessary due to both factors: the growing level of radio frequency interference (RFI) signals at actual site and requirements of rising up a new building at the BSS antenna location. We present results of RFI signals search at INPE-Cachoeira Paulista area as purpose to define a new BSS site.

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