ABSTRACT
This chapter describes the functions and performance specifications of the principal components of the satellite earth stations used for the transmission and distribution of radio and television programs. Earth station antennas must be highly directional. Antennas with one feed horn system have a single beam, while multiple feed horns can be used to produce multiple beams. In the most basic single-beam-antenna configuration, the reflector is a section of a paraboloid; and the feed horn, located at its focus, illuminates it directly. Multiple-beam antennas are used in downlink earth stations that receive signals from several satellites, for example, at cable TV head-ends. The most important electrical performance criteria of transmitting and receiving antennas are directivity, gain, and polarization isolation. An earth station should have available all the standard test equipment, such as signal generators and oscilloscopes, which are required for communication systems operating in the gigahertz frequency range.
