Television became the main market, its demand for simultaneous delivery of relatively few signals of large bandwidth to many receivers being a more precise match for the capabilities of geosynchronous comsats.
Two satellite types are used for North American television and radio:
Direct Broadcast Satellite (DBS),
A direct broadcast satellite is a communications satellite that transmits to small DBS satellite dishes (usually 18 to 24 inches in diameter). Direct broadcast satellites generally operate in the upper portion of the microwave Ku band. DBS technology is used for DTH-oriented (Direct-To-Home) satellite TV services, such as DirecTV, DISH Network , and Sky Angel in the United States, ExpressVu in Canada, and Sky Digital in the UK, Republic of Ireland and New Zealand.
Fixed Service Satellites use the C band, and the lower portions of the Ku bands. They are normally used for broadcast feeds to and from television networks and local affiliate stations (such as program feeds for network and syndicated programming, live shots, and backhauls), as well as being used for distance learning by schools and universities, business television (BTV), Videoconferencing, and general commercial telecommunications. FSS satellites are also used to distribute national cable channels to cable TV headends.
Fixed Service Satellites (FSS)
FSS satellites differ from DBS satellites in that they have a lower RF power output than the latter, requiring a much larger dish for reception (3 to 8 feet in diameter for Ku band, and 12 feet on up for C band), as well as using linear polarization for each of the transponders' RF input and output (as opposed to circular polarization used by DBS satellites). FSS satellite technology was also originally used for DTH satellite TV from the late 1970s to the early 1990s in the United States in the form of TVRO (TeleVision Receive Only) receivers and dishes (also known as big-dish, or more pejoratively known as "BUD" or "Big ugly dish" systems). It was also used in its Ku band form for the now-defunct Primestar satellite TV service.
Satellite TV
Posted by Mark Gabrielle