Abstract :
Three types of direct-to-home broadcast satellite (DBS), or "DBS-like," services are currently being developed or used in the United States. The earliest service to be used depends upon low-power 5-10 W 6/4 GHz2satellite transponders, which operate in the fixed-satellite service (FSS) to provide predominantly unscrambled TV programs to cable head ends and other local terrestrial distribution systems. Some 600000 viewers are using individual 3 m "dishes" to eavesdrop on scores of "free" channels. The second DBS service to begin operation uses dedicated medium-power 14/11 GHz FSS transponders, which provide subscription service to some 10000 home terminals equipped with antennas in the 1-2 m diameter range. Finally, the high-power DBS service, which is under active development using the 17/12 GHz broadcasting-satellite service (BSS) band, can provide high-quality television pictures from dedicated 200 W satellite transponders to inexpensive home terminal antennas as small as 60 cm. Which service-low-, medium-, or high-power-is best? The home terminal equipment cost decreases as the transponder power increases, for the same picture quality and area of coverage. However, more varied and less costly programming is available now in the 6/4 GHz band than in the higher-frequency bands. From the viewer\´s perspective, continued competition between these services, and with other home video delivery services such as CATV and prerecorded cassettes, should provide the best choice of programming at the least cost. From the more challenging perspective of the DBS system operator, the best means to this desirable end will depend on the number of viewers, on the programming quality, cost, and availability to the operator, on the cost of the space segment, and on the obstrusiveness and cost of the home terminal.