On the System Design of Low-Cost Ground Stations for Satellite Communications

Abstract The main design factors for a satellite communications ground station are reviewed and various sections of the stations, where the design is critical, especially the antenna and drive systems, are discussed in more detail with regard to recent results and proposals . The system design is normalized with respect to the maximum power flux recommended by CCIR, and it is found that present satellite systems do not even approach this maximum level. In the system design, influences of various sorts, f.ex. influence of heavy precipitation is included. In a design example, considering only the receiver part of the station, power flux levels comparable to that of early experimental satellites are used and it is concluded, that a Cassegrain type of antenna with a nitrogen cooled parametric amplifier tends to be the most economical for station sites outside tropical regions. In some tropical regions, additional attenuation due to heavy precipitation will require antenna areas far in excess of those currently used (up to app. 25 meters diameter), if the present rather low power flux from satellites is used. Then, if the transmitter power and/or antenna gains for the satellites are increased to compensate for this, stations in temperate climates will probably be designed with antenna areas determined by their function as transmitters and/or by interference consideration rather than by their function as a part of a low noise receiver.