Direct broadcasting satellite
Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location. The signals are received via an outdoor parabolic antenna usually referred to as a satellite dish and a low-noise block downconverter.
A satellite receiver then decodes the desired television programme for viewing on a television set. Receivers can be external set-top boxes, or a built-in television tuner. Satellite television provides a wide range of channels and services. It is the only television available in many remote geographic areas without terrestrial television or cable television service.
Modern systems signals are relayed from a communications satellite on the Ku band frequencies (12–18 GHz) requiring only a small dish less than a meter in diameter. The first satellite TV systems were an obsolete type now known as television receive-only. These systems received weaker analog signals transmitted in the C-band (4–8 GHz) from FSS type satellites, requiring the use of large 2-3 meter dishes. Consequently, these systems were nicknamed "big dish" systems, and were more expensive and less popular.
Early systems used analog signals, but modern ones use digital signals which allow transmission of the modern television standard high-definition television, due to the significantly improved spectral efficiency of digital broadcasting.
...
Wikipedia