Satellite Communications refer to the communications between a satellite in space and a radio station on the ground. This communications system is characterized for its wide coverage, disaster-proofness, and broadcast capability. Therefore, users of this system take advantage of these characteristic features.
The communication satellite is mainly used as a fixed line on which international telephone relays, transmission of content for television programs and the similar uses are made. In addition, it is increasingly used as a leased circuit for communications within corporations, for communications among local governments for administrative disaster prevention
In case the communication satellite is used as a fixed line, it is necessary to have a big antenna with more than five meters in diameter.
When the content for the television programs need to be transmitted from the site where it is collected, a vehicle such as a truck with an in-vehicle two-meter-diameter antenna is used.
The communication satellites with a one-meter-diameter antenna are called VSAT and are widely used for the administrative communication system for disaster prevention.
