Site diversity is one of six techniques used to improve the reliability of satellite communications by limit atmospheric effects, particularly those caused by rain fade.
A diversity scheme is typically required when using frequencies in the Ka, V, or W-band.
The downlink transmissions of satellites cover very large areas, that will have different weather.
These intense rain areas, for example, supercells, often have a horizontal length of no more than a few kilometers: putting the ground stations at a sufficient distance the possibility of rain fade in the downlink signal will be reduced.
Site diversity systems have been known to minimize disruption of service by major satellite carriers.