Impact of seasonal and diurnal variations on satellite system design in V band

In the framework of the ITALSAT campaign various European institutions carried out propagation measurements at V band. In this frequency band, signal reception in a satellite-to-Earth or Earth-to-satellite path may suffer severely from signal attenuation due to meteorological effects such as rain, snow, hail, fog, clouds, etc., where rain provides the most significant contribution. In this paper, a joint analysis of the ITALSAT propagation measurement campaigns at 39.6 GHz (precisely 39.592 GHz) carried out at both Oberpfaffenhofen, close to Munich, Germany, and Spino d´Adda, close to Milan, Italy, is presented. For both stations long-term attenuation statistics are available and reveal that signal attenuation due to meteorological effects depends very much on the season and on the time of the day. Signal attenuation can be compensated by an appropriate fade margin. In this paper, we show that the required fade margin to guarantee a target link availability has to be chosen very carefully, since it depends very much on the time interval upon which availability is defined. We consider complete years, ITU-R recommendations, all single months of the year, worst months, and spring, summer, fall, and winter. Furthermore, we evaluate diurnal variations for four time intervals: 00:00-06:00, 06:00-12:00, 12:00-18:00, and 18:00-24:00.