Relay Station Using Satellite
Communication satellites are used as relay station for other sources. If a transmitting station cannot communicate directly with other receiving station because of line of sight restriction, then a satellite is used as a repeater. The transmitting station sends information to satellite which retransmits it to the receiving station.
Earth station transmits information to the satellite. Then transmitted signal receive by receiver in the satellite. Satellite amplifies the signal and converts it into another frequency. The original signal being transmitted to the satellite from the earth station is known as up-link. In C band up-link frequencies are in range 5.925GHz to 6.425GHz.This retransmitted signal from the satellite to the receiving station is known as down-link and is frequency range is lower than that of up-link frequency.