Accession Number : ADP006885

Title :   Some Considerations Concerning Low Noise Radio Receiving Systems,

Corporate Author : NORWEGIAN TELECOMMUNICATIONS REGULATORY AUTHORITY OSLO

Personal Author(s) : Stokke, Knut N.

Report Date : JUN 1991

Pagination or Media Count : 13

Abstract : In order to get a good signal to noise ratio at very high radio frequencies (higher than 20 - 40 MHz), low noise amplifiers are often used. Such amplifiers should have a very low total noise factor (noise figure). Normally it is the noise factor of the first stage of an amplifier which is decisive for the total noise factor. Losses in a system will also influence the noise factor of a system. Consequently the losses in cables and waveguides must be taken into account when considering the total noise factor. The thermal noise radiation from the surroundings may increase the noise temperature of an antenna. For reflector antennas, such as parabolic reflector antennas, the noise temperature is dependent on the elevation angle, and also dependent on the fors of the surroundings, mountains, hills, buildings, etc. The measurements referred to in this article, were done by the Radio interference Division in the Norwegian Telecom.

Descriptors :   *NOISE(RADIO), *RADIOFREQUENCY AMPLIFIERS, *PARABOLIC ANTENNAS, *COMMUNICATION AND RADIO SYSTEMS, AMPLIFIERS, ANGLES, ANTENNAS, BUILDINGS, CABLES, ELEVATION, INTERFERENCE, LOSSES, LOW NOISE, LOW NOISE AMPLIFIERS, MOUNTAINS, RADIATION, RADIO INTERFERENCE, RATIOS, REFLECTORS, SIGNAL TO NOISE RATIO, SIGNALS, TEMPERATURE, WAVEGUIDES, RADIOFREQUENCY, NOISE(ELECTRICAL AND ELECTROMAGNETIC), TRANSMISSION LOSS, RADIO RECEIVERS, REPRINTS, SYMPOSIA.

Subject Categories : Electrical and Electronic Equipment
      Radio Communications
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE