TABLE OF CONTENTS For the purposes of this discussion, an Earth station can be broken down into the following major elements: the RF terminal (including the antenna), the baseband and the control equipment, and the user interface. In addition to these electronic systems, every fixed Earth station must be supported by a physical facility capable of housing the equipment, supplying reliable electrical power, and maintaining the temperature and humidity of the electronics within acceptable limits. These latter functions are similar to the ones provided by the spacecraft bus (while the functions in the previous sentence are comparable to those of the communications payload). The key difference here is that the majority of operating Earth stations can be serviced by maintenance personnel and externally powered. That allows the larger Earth stations to be designed from building blocks that consume lots of power and are easily repaired or changed.
The previous remarks obviously apply to the traditional type of permanent Earth station such as what is used to uplink digital TV. Modern UTs, such as advanced TVRO terminals and MSS phones, are self-contained and some are battery powered. Just like consumer electronics, UTs of this class do not require servicing except for setup (such as a user would do with a mobile phone) and replacement of batteries. Repairs are performed by taking the unit to a repair facility or, in the case of the ultimate consumable electronic item, simply throwing it away as one would an obsolete PC or mobile...
