Terrestrial radio propagated by sending and receiving line of sight signals from the relay station to the receiving antenna. However, the curvature of the earth was a barrier to further relay. Satellite radio was the solution to this dilemma.

Instead of earth relay stations, Satellite Radio uses communication satellites (Geostationary satellites) to relay signals, resulting in almost comprehensive coverage. Reception requires an antenna which is small enough as the signal is strong; however, it requires line of sight access between the antenna and the satellite and reception becomes problematic in tunnels or cityscape. However, local booster repeaters are being installed in cities which solves this problem altogether.

Each receiver is assigned an Electronic Serial Number to uniquely identify it, and upon subscription to the Sat Radio service, authorization code is sent which enables reception of stations. Service is provided by commercial business entities, and is primarily provided by WorldSpace, XM Radio and Sirius. Satellite Radio is substantially different from AM/FM radios or the Digital Television Radio (DTR). SR is subscription based although one or more channels may be made available as Free to Air. SR can be portable, unlike DTR, but like AM/FM. It’s reach is very high. Sound quality is usually better than FM. Variety and depth of programming is highest. As a subscription based medium, commercial interference is low or none.

With very less government regulation, unlike AM/FM, satellite radio has very good scope of innovation. Lowering of user charges and high quality, apart from high availability, make them dear to connoisseurs of music or news hungry around the world.