How Satellite TV Works
Satellite TV transmits by using satellites located 22,000 miles above earth. Broadcasting from this height directly down to earth increases the signal strength and can ultimately reach a larger range of subscribers than terrestrial broadcasting TV land antennas. Satellite television systems transmit and receive radio signals using specialized antennas called satellite dishes. The subscriber’s dish receives the signal from the satellite (or multiple satellites in the same part of the sky) and passes it on to the receiver in the subscriber's house. The receiver processes the signal from the dish and is carried through cables to a standard television.
The reflector (the concave dish-shaped part of the antenna) and the feed horn (the part of the antenna that is mounted on an arm that projects out from the dish) make up the two parts of the satellite dish.
The reflector captures and focuses the satellite signal onto the feed horn which takes the signal and feeds it through a cable to the satellite receiver (the box). Newer satellite dish designs pick up several satellites through multiple feed horns, providing more programming options. the feed horn has a feature known as a low noise block down converter (LNB) which provides a clear signal.
Television satellites are all in geosynchronous orbit, meaning that they are at a fixed point in space relative to the Earth. Each satellite is launched into space at about 7,000 mph (11,000 kph), reaching roughly 22,200 miles (35,700 km) above the Earth. At this speed and altitude, the satellite will revolve around the planet once every 24 hours -- the same period of time it takes the Earth to make one full rotation. The dish is then directed to the satellite and functions consistently after the initial transmission configuration.
The typical satellite TV viewer receives programming from a direct broadcast satellite (DBS) provider. There are two main DBS providers in the U.S., DirecTV and Dish Network. A subscriber to one of these providers is furnished with a direct to home (DTH) satellite system consisting of the following five parts.
* Programming sources- the satellite providers do not create the programming but function like cable TV, supplying the viewers with hundreds of channels in a set package of programming which the Satellite provider pays other companies for the right to broadcast their content via the satellite.. The satellite provider is the medium between the user and the content provider. * The DBS broadcast center- This central hub transmits the content that is beamed by the provider to its broadcast satellites, which in turn beam the content to the dish antenna. * The satellites- Satellites receive signals from the DBS broadcast center and send those signals to subscriber antennas on the ground. * The dish. The dish is the subscriber's antenna, picking up the satellite signal and sending it, using a cable, to the receiver (or box). * The receiver. The receiver is the device that decodes the satellite signal and transmits it to the actual television set.
In viewing and using the Satellite TV system, the provider's broadcast is completely digital, which improves upon picture and sound quality. Early satellite television was broadcast in C-band radio -- radio in the 3.4-gigahertz (GHz) to 7-GHz frequency range. Digital broadcast satellite transmits programming in the Ku frequency range (12 GHz to 14 GHz ).
Written by David Johnson.