Satellite radio’s popularity is growing rapidly nationwide. The leading provider, XM, claims it has 2 million subscribers, and smaller competitor Sirius Satellite Radio recently said it has 500,000 subscribers.

The two companies now offer a total of 133 commercial-free music channels and 88 of talk radio. Both XM and Sirius are racing to launch new technology and programming.

Satellite channels beam their signals to a satellite orbiting more than 22,000 miles above the earth, which then transmits them to radio receivers in cars and homes. Subscribers buy receivers, priced as low as $50, to receive the service. The technology allows listeners to hear the same station anywhere in the continental United States.

The Federal Communications Commission initially opened up bandwidth on its satellites for commercial broadcast in 1997. Four companies paid $80 million each to access the spectrum.

Washington-based XM signed up its first customers by September 2001, and Sirius followed in 2002. The two companies are now the only broadcasters in the United States, but satellite radio is also available in more than a dozen nations in Europe and Asia.

More here.