TABLE OF CONTENTS The terrestrial interface can be called the "business end' of the Earth station because it is where the actual user services are made available. In larger stations, the terrestrial interface can be quite complex, as suggested in Figure 9.1. A gateway station looks to the outside world like a traffic node or a portion of a broadcasting studio, depending on the application. On the other hand, simple terminals such as a TVRO or a VSAT render their services directly to consumer equipment, like a TV set or a PC, respectively. A handheld UT may have no external interface since it is a self-contained unit. The requirements of the terrestrial interface, therefore, vary widely based on the application and user facility provided.
A terrestrial tail may be needed to connect the communications Earth station to one or more remote user locations. The distance to be covered can range from a few meters to hundreds of kilometers. In C-band satellite systems, the Earth station is often isolated from a city to reduce terrestrial interference, in which case an elaborate tail is required. On the other hand, terrestrial interference is not present in most Ku- and Ka-band systems; therefore, tails can be relatively short. An exception is the case where a large Earth station (i.e., a teleport) is shared by several users each of which must be reached by local terrestrial transmission links, often provided by local telecommunications carriers. Site diversity may be...
