Commercial-free digital radio via satellite from SiriusXM Satellite Radio (www.siriusxmradio.com). For a monthly fee, or a single-payment lifetime fee per radio, satellite radio offers more than 120 channels of music, news, sports, weather and talk. Unlike AM, FM and HD terrestrial radio, the satellite channels are consistently available throughout the U.S. as long as there is sufficient line of sight to the satellites. Subscribers can optionally radio service to their PCs, smartphones and Internet radios.
Home, Car and Portable
Nearly all automobiles include satellite tuners in their radios, which typically provide a period of free service before requiring a paid subscription. For non-satellite radios, portable units plug into the car's audio system, as well as a home stereo. For older cars that do not have external audio jacks, some portable units output an FM signal that is picked up by the car's FM tuner. See DAB
Launched respectively in 2001 and 2002, XM Satellite Radio and Sirius Satellite Radio competed for business until 2007, when they merged to become SiriusXM Satellite Radio. Extra-cost premium channels were duplicated on both services so that XM users could optionally add the "Best of Sirius," and Sirius subscribers could obtain the "Best of XM."
Satellite and Terrestrial Transmission
The Sirius system uses satellites that transmit in the 2320-2332.5 MHz range, while XM uses 2332.5-2345 MHz. Using frequencies in the center of their respective ranges, both systems employ terrestrial transmission to augment the satellites in cities with tall buildings and in areas with strong interference. See HEO
At Home; On the Road
This early unit included a line out for the car's audio system, as well as an FM station transmitter that the car's radio could tune into. At home, it plugged into a docking station for connection to a stereo. (Image courtesy of Sirius Satellite Radio, www.siriusxm.com)