transponderA radio or radar system that is triggered by a received signal. Transponders are important components of communications satellites and consist of a receiver, a frequency converter, and transmitter package. They have a typical output of 5–10 watts, operate over a 36–72 MHz bandwidth in the L-, C-, Ku-, or Ka-band, except for mobile satellite communications. Communications satellites typically have 12–24 onboard transponders, although the Intelsat VI at the extreme end has 50. Related category• SPACECRAFT COMMUNICATIONS AND TRACKINGAlso on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History |