Long-term performance of antenna systems for satellite broadcasting reception

Direct broadcast from a satellite (DBS) is in commercial use in Japan. Several types of receiving antenna systems are manufactured. Since the antennas are in general placed outdoors, the performance of the receiving antenna systems is affected by weather conditions. For example, snow accretion or raindrops on the antennas decrease signal power. This decrease can be evaluated by deterioration of gain (G) of the antennas. Also, the snow or raindrops can generate noise, which is evaluated by increase of an equivalent noise temperature (T). Thus, it is important to observe a figure of merit (G/T) over a long period. This is useful for developing new receiving antenna systems and for choosing adequate antennas. This paper presents long-term observation results of the G/T for three types of antenna systems. We discuss the effects of the weather conditions.<>