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The Basics
Using satellites to distribute radio broadcasts is an idea over 10 years in the making. In 1992, the U.S. Federal Communications Commission (FCC) allocated a new spectrum in the "S" band (2.3 GHz) for nationwide broadcasting of satellite-based Digital Audio Radio Service (DARS). There were four companies that applied for licenses to broadcast over that band. The FCC gave licenses to two of those companies in 1997. CD Radio (now Sirius Satellite Radio) and American Mobile Radio (now XM Satellite Radio) paid more than $80 million each to use space in the S-band for digital satellite transmission.Sirius Satellite Radio is operational in the United States, with its official launch on July 1, 2002.
Sirius Satellite Radio
Sirius uses three SS/L-1300 satellites to form an inclined elliptical satellite constellation. Sirius says that having an elliptical path for their satellite constellation ensures that each satellite spends roughly 16 hours a day over the United States, with at least one satellite over the country at all times. Sirius completed its three-satellite constellation in November 2000. They keep a fourth satellite on the ground, ready to be launched if any of the three active satellites encounter problems.
The satellites have programs beamed to
the three Sirius satellites, which then transmit the signal
back to the
ground, where your radio picks up one of the stations within
the signal. Signals are also beamed to repeaters on the ground
for subscribers in urban areas where the satellite signal can be disrupted
by tall objects like buildings.
Sirius produces car radios and home entertainment systems, as well as car and home kits for portable use. The receiver includes two parts which are the antenna and the receiver. The antenna picks up the signals from the satellite, amplifies the signal and filters out any interference. The signal is passed on to the receiver. Inside the receiver are special computer chips that converts the signals for play.