4-GC transmission degradation due to rain at the andover, maine, satellite station

The microwave link between a ground station and a communications satellite is normally vcry sta ble and essentially free from fading. Under conditions of rain or snow, however, the transmitted and received signals encounter cxtrn attenuation and additional noise is introduced into the low-noise receiver on the ground. A good knowledge of such rain effects is important for the design of satellite ground stations which have to meet certain statistical requirements for transmission degradation. It is known that radome covered ground stations like Andover, suffer more degradation during rain than uncovered stations. Some analytical work has been done by D. Gibble
¹
and B. C. Blevis
²
to determine the effects of a water layer on radomes. Their theoretical work has been supplemented by an experimental technique applicable at existing satellite ground stations and to be described in this brief report. It consists of measuring the reduction of the noise power received from the strong and stable radio star Cassiopeia A during periods of rain.