The Raisting Satellite Earth Station and Its System Noise Temperature

Features of the German satellite earth station at Raisting are cited in this paper. One essential criterion, the noise performance, is discussed in particular. The 25-meter Cassegrain antenna with horn reflector feed (covered by a radome) has been subjected to extended measurements of the system noise temperature. The results show the relation between the system noise temperature and the antenna elevation and azimuth angles under different weather conditions. In fair weather the system noise temperature is
53/deg
K with an elevation of 5° giving a ratio of antenna gain and system noise temperature of 40.7 dB. The curve of the system noise temperature at low elevation angles corresponds well to the optical horizon. During rain an increase of the system noise temperature has been noted. After rain, however, normal conditions are soon restored.