Communication Satellites

Communication Satellites Geostationary Satellites • Medium-Earth Orbit Satellites • Low-Earth Orbit Satellites • Satellites versus Fiber Communication Satellites Communication satellite can be thought of as a big microwave repeater in the sky. It contains several transponders, each of which listens to some portion of the spectrum, amplifies the incoming signal, and then rebroadcasts it at another frequency to avoid interference with the incoming signal. Geostationary Satellites maximum 180 satellites(360/2) Orbit slot allocation is done by ITU(International Telecommunication Union). station keeping: The effects of solar, lunar and planetary gravity tend to move them away from their assigned orbit slots and orientation. ITU has allocated certain frequency bands to satellite users. Medium-Earth Orbit Satellites Takes around 6 hours to circle the earth. Compared to GEOs they have smaller footprint on the ground and requires less powerfull transmitters to reach them. Eg: GPS(Global Positioning System) satellites orbiting at about 18,000 km.

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