Rain fade compensation for spacecraft antennas

Various atmospheric conditions cause attenuation in the signal received from broadcast satellites. The total attenuation consists of losses due to cloud, atmospheric scintillation, oxygen absorption, water vapour and rain. The rain attenuation is usually the most important one of these and at 22 GHz can produce fade-margins of up to 20 dB with considerable and comparatively rapid geographical and temporal variation. It is, therefore, important to try to compensate for fading due to atmospheric effects to achieve a better power flux density over the satellite coverage area. The paper discusses the practical implementation of such compensation for the Italian high definition TV transmission. The data base and algorithms used to obtain atmospheric attenuation information were reported by Paraboni et al. (1994)