Satellite television or satellite TV is television delivered by way of orbiting communications satellites located 37,000 km above the earth's surface.
The first satellite TV signal was relayed from Europe to the Telstar satellite over North America in 1962. The first domestic North American satellite to carry television was Canada's Anik 1, which was launched in 1973.
Satellite TV, like other communications relayed by satellite, starts with a transmitting satellite antenna located at an uplink facility. Uplink satellite dishes are directed toward the satellite that its signals will be transmitted to, and are very large, as much as 9 to 12 meters (30 to 40 feet) in diameter. The larger the satellite dish, the more accurate positioning and improved signal reception at the satellite. The satellite TV signals is transmitted to devices located on-board the satellite called transponders, which retransmit the satellite signal back towards the Earth at a different frequency.
The satellite signal, quite weak after traveling through space, is collected by a parabolic receiving dish, which reflects the weak signal to the dish's focal point and is received, down-converted to a lower frequency band and amplified by a device called a low-noise block down converter, or LNB.
A new form of satellite antenna, which does not use a directed parabolic dish and can be used on a mobile platform such as a vehicle, was recently announced by the University of Waterloo. On commonly known as car satellite system.
The satellite TV signal, now amplified, travels to a satellite TV receiver box through coaxial cable (RG-6 or RG-10; cannot be standard RG-59) and is converted by a local oscillator to the L-band range of frequencies (approximately). Special on-board electronics in the receiver box help tune the signal and then convert it to a frequency that a standard television can use.
As you known, satellite TV business in United States are mainly dominated by two companies, Dish Network and DirecTV. If you would like to have a satellite TV in your home, your choices are mostly limited to the free satellite TV packages that offered by either one Dish Network or DirecTV.
Here’s a quick view on United States satellite TV industry: Hughes's DirecTV, the first high-powered DBS system, went online in 1994 and was the first North American DBS service. In 1996, Echostar's Dish Network went online in the United States and has gone on to similar success.
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