TABLE OF CONTENTS Satellites provide broadcast transmissions in the fullest sense of the word, because antenna footprints can be made to cover large areas of the earth. The idea of using satellites to provide direct transmissions into the home has been around for many years, and the services provided are known generally as direct broadcast satellite (DBS) services. Broadcast services include audio, television, and Internet services. Direct broadcast television, which is digital TV, is the subject of this chapter.
A comprehensive overview covering the early years of DBS in Europe, the United States, and other countries is given in Prichard and Ogata (1990). Some of the regulatory and commercial aspects of European DBS will be found in Chaplin (1992), and the U.S. market is discussed in Reinhart (1990). Reinhart defines three categories of U.S. DBS systems, shown in Table 1.4. Of interest to the topic of this chapter is the high power category, the primary intended use of which is for DBS.
From Table 1.4 it is seen that the orbital spacing is 9 for the high-power satellites, so adjacent satellite interference is considered nonexistent. The DBS orbital positions along with the transponder allocations for the United States are shown in Fig. 16.1. It should be noted that although the DBS services are spaced by 9 , clusters of satellites occupy the nominal orbital positions. For example, the following satellites are located at 119 W longitude: EchoStar VI, launched on July 14, 2000; EchoStar IV, launched...
