Satellite Radio

A satellite radio is a digital radio that broadcasts from communications satellites and typically covers a much wider geographic area than terrestrial radio signals. It is often subscription based. There have been three major satellite radio companies: WorldSpace, Sirius and XM. All started in the 1990s and were competing in the US satellite radio market. In 2008 XM and Sirius merged to form SiriusXM Radio. SiriusXM maintained the Sirius and XM brand and continued to make the older satellite radios and receivers but now allows multiple devices per account.

The satellite radio system works by transmitting programming to satellites that orbit Earth and then bounce the signal back down to specialized radio receivers—usually installed in cars and home stereo systems—using channels in the 2.3-gigahertz (GHz) S band of the electromagnetic spectrum. A terrestrial repeater network also helps transmit the signal into buildings and around obstacles such as hills.

The incoming digital audio signals are then digitized, error-corrected, demodulated, and decrypted by a microprocessor in the radio receiver. The receiver also has a circuit that combines multiple receivers, called a maximal-ratio combiner, to get better sound quality and eliminate interference from other signals.

Listeners pay a monthly fee for the service to hear thousands of channels, commercial-free. They can choose from music (including classic ’80s hair bands, the Grateful Dead, and emotional driven alt rock) to news, sports, talk, comedy, movies, and more. Unlike terrestrial radio, satellite radio is available everywhere you go—as long as there’s a clear sky.