Satellite that broadcast audio, data and video to vast regions of the earth below are high power, complex switching and frequency translation relay devices. Modern communication satellites receive signals, typically in the 1 to 40 GHz range, amplify and process these signals, and then downconvert their frequency for broadcast to a target area on the earth below. Each transponder processes signals with a given center frequency that spans a specified frequency band and has a predetermined EIRP. Today satellites that relay L-band, S-band, C-band, Ku-band and Ka-band signals are common. C-band video satellites typically have 24 transponders, or separate channels, on-board. The channel structure of Ku-band spacecraft is generally more variable. Today numerous spacecraft have transponders designed to handle more than one frequency band.ch satellite can be defined by a number of parameters including the number of channels, downlink power, antenna coverage and frequency transmitted.