We all have our favorite radio stations that we preset into our car radios, flipping between them as we drive to and from work, on errands and around town. But when travel too far away from the source station, the signal breaks up and fades into static. Most radio signals can only travel about 30 or 40 miles from their source. On long trips that find you passing through different cities, you might have to change radio stations every hour or so as the signals fade in and out.
Now, imagine a radio station that can broadcast its signal from more than 22,000 miles (35,000 kill) away and then come through on your car radio with complete clarity without ever having to change the radio station. Satellite Radio or Digital Audio Radio Service (DARS) is a subscriber based radio service that is broadcast directly from satellites. Subscribers will be able to receive up to100 radio channels featuring Compact Disk digital quality music, news, weather, sports. talk radio and other entertainment channels.
The satellite era began in September 2001 when XM launched in selected markets. followed by full nationwide service in November. Sirius lagged slightly, with a gradual rollout beginning in February, including a quiet launch in the Bay Area on June 15. The nationwide launch comes July 1. To the average user, these systems will look very similar to conventional AM/FM .radio systems, whether they are used in the home, office, or on the road. However. the real difference is in what the listener won't see. Rather than receiving a signal from a tower antenna of a local radio station, these new radios will receive signals from a set of satellites in geosynchronous orbit. Programming will be up linked from ground stations to the satellites and then broadcast back to large geographic areas.
XM Satellite Radio launched commercial service in limited areas of the United States on September 25, 2001. (They were originally going to launch service September 12. but postponed the event because of the terrorist attacks on the United States.)
Sirius Satellite Radio is now operational in the United States, with its official launch on July I, 2002.
WorldSpace is already broadcasting in Africa and Asia, and will begin broadcasting in South America sometime soon.
XM Satellite radio and Sirius Satellite Radio have both launched such a service. Satellite radio, also called digital radio, offers' uninterrupted, near CD quality music beamed to the radio from space.
The Sirius system is similar to that of XM. Programs are beamed to one of the three Sirius satellites, which then transmit the signal to the ground where the radio receiver picks up one of the channels within the signal. Signals are also be beamed to ground repeaters for listeners in urban areas where the satellite signal-can be interrupted. While XM offers both car and portable radios, Sirius is concentrating on the car radio market. Sirius also offers an adapter that allows conventional car radios to receive satellite signals.
WorldSpace has been the leader in the satellite radio industry.WorldSpace does plan to reach the corners of our world that most radio stations cannot . There are millions of people living in WorldSpace's projected listening area who cannot conventional radio station. WorldSpace says it has a potential audience of about 4.6 billion listeners spanning five continents.