Direct Satellite Broadcasting - Longterm-Study on Video Transmissions at 11.6 GHz using the OTS Satellite

In the frame work of a test programme established by the European Broadcasting Union, long-term studies (almost 3000 hours of transmission) have been carried out using the OTS-Satellite to investigate the influence of the atmosphere on a frequency-modulated TV signal under real conditions. The characteristics of the signal were generally in accordance with the specifications determined by the World Administrative Radio Conference on Broadcasting Satellites (WARC-BS), held in Geneva 1977. The main conclusion from these investigations is that with the exception of the signal-to-noise ratio, which is of course dependant upon fading of the signal, neither linear nor non-linear distortions of the demodulated video signal may be attributed to atmospheric events such as rain showers or snow falls. Other results were the derivation of a cummulative distribution for these long-term TV transmissions as well as the determination of a correlation between fading and the degradation of the signal-to-noise ratio.