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Here is some information about satellite TV.
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.
Teddy Low
Webmaster
http://www.satellitetvissue.com |
