How Does Free to Air Satellite Work?by Quinten Plummer
Free to air satellites (FTA) require no subscription, unlike premium satellite services. The signals are unencrypted. Televisions stations beam their programming via radio waves to satellites orbiting the earth. The satellites orbit the earth, moving at the same speed as the earth. So on the ground, the satellites seem like stationary objects--and satellite dishes can "lock on" to them. When the satellites receive the signals, they beam them down towards earth.
The radio signals contains the raw data that makes up the audio and video being sent from the television station. Unlike the signals from pay services, like Dish Network and Direct TV, the signal from FTA satellites isn't scrambled. Pay satellite services are like cable companies, in that they buy premium programming from networks and encrypt the signal so that you have to subscribe to their services to use their signal. FTA is more like using an antenna to find unencrypted stations.
The curved dish directs the signal to the LNB receptor, positioned over the center of the dish. The dish must have a clear path to the satellite without any obstructions like trees or buildings. The dish receives the signal at the LNB, strengthens it, and then passes it along to the receiver.
The receiver decodes the signal and performs any necessary decompression--most high definition channels are uncompressed. While FTA signals don't require a specific receiver, they do require that your receiver be compatible with the station's signal format--the most popular is MPEG-2 for video compression.
- http://commons.wikimedia.org/wiki/File:Sky_minidish.JPG, Maksim