PURPOSE: To obtain a reception power deterioration compensating system which compensates attenuation due to rainfall generated on a communication schannel in satellite communications by a satellite communications earth station on a reception side.

CONSTITUTION: The satellite communications earth station 1 on the reception side is constituted of an antenna 2 which receives a signal sent from a satellite communications earth station on a transmission side via a satellite, a first low noise amplifier 3 and a second low noise amplifier 4 which amplify the signal received by the antenna 2, and a first switch 5 and a second switch 6 used by switching the first or second low noise amplifier corresponding to the attenuation of a received wave. By employing such constitution, it is possible to improve the reception performance index of the satellite communications earth station 1 on the reception side and to compensate the attenuation due to the rainfall, etc., by guiding a reception signal from the antenna by switching the switches 5, 6 when the attenuation of the wave due to the rainfall, etc., occurs on the communications channel.