Summary A transponder is a device for receiving and rebroadcasting a signal. Usually, this signal is amplified by the transponder, and can be encoded or modified in other ways. Satellite transponders are a part of the payload of a satellite and are used for receiving and transmission of uplinked signals. The signals transmitted from earth are received by the satellites at very low power level due to the big distance difference between the transmitter and the satellite. The transponders on the sa