| Friday, October 1, 2010 |

How Does Directv Satellite Technology Work?

First of all, unlike earlier satellite communications which relied on a motorized dish to chase the mobile satellites across the sky, modern satellites are placed into a geosynchronous orbit about 37,000 km (22,300 miles) up. This means that they always remain above the same point on the earth's surface. That way, all dishes on the earth can be pointed at a fixed location, and the satellite will always be there.

The signal to be broadcast originates at an "uplink center", which collects nationwide programming from cable television networks and local programming from broadcast networks and encrypts it so that the programming cannot be intercepted by non-paying users. The uplink facility uses a huge dish, 9 to 12 meters (or 30 to 40 feet) wide, to accurately send a high-strength signal to the orbiting satellite.

The satellite, in turn, converts the signal to a different microwave frequency band, so that the downlink doesn't cause interference with the uplink. The two most common frequencies used in United States satellite tv broadcasts are the "C-band" (4 to 6 GHz) and the "Ku band" (12 to 18 GHz).

After traveling more than 50,000 miles, and being converted in between, the signal that arrives at the receiving dish on the outside of the consumer's home is fairly weak. It is focused by a bowl-shaped parabolic dish onto a device in the center called a "feed horn", which channels the signal to a "low-noise block downconverter" (LNB) which filters out unwanted interference, and sometimes converts it to yet another frequency before amplifying it and sending it to the satellite receiver box inside the house through a coaxial cable.

The satellite receiver box converts the signal to an analog television, audio or data signal. The receiver may be equipped to decrypt the coded signal itself, or it may require a separate box or a "smart card" plug-in (either to the receiver box or to the television to perform the decoding. A single receiver can serve only one television or computer; multiple receivers must be purchased to provide signal to multiple devices, including watching one channel and recording on another.

Many receivers also include integrated digital video recorders (DVR), allowing them to rewind and pause live television, and to record and store their favorite shows on a built-in hard drive. There are also increasing numbers of high-definition television (HDTV) satellite receivers and DVRs available.

Newer technologies being integrated into the system include pay-per-view functionality, interactive television channels, and video-on-demand (VOD) channels.

The competition for between satellite tv providers, and between satellite and cable providers, is quite fierce. The advantages of being the first to provide new features are driving the pace of invention among satellite technology providers, so we can expect to see many more breakthroughs in the near future.


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