The most popular type of DARS in the U.S. and Canada is SDARS: Satellite Digital Audio Radio Service, used by Sirius Satellite Radio and XM Satellite Radio. XM and Sirius both operate in the 2.3-GHz S band, from 2320 to 2345 MHz.
Increasing the spectrum available for more services would be difficult, since unlike C-band and Ku band services, which allow over 200 locations for satellites, S-band satellites must be spaced far apart, with current technology. Existing vehicle antennas would not allow reception of two different stations on the same frequency, though new technology, requiring a new kind of receiver, might be possible.
Digital Satellite Broadcasting Corporation was one of four companies bidding for Satellite Digital Audio Radio Service, or SDARS, licenses in the United States. The service would have been a listener-supported subscription digital audio service.
1997 April: American Mobile Satellite Corporation and Satellite CD Radio, Inc. are each awarded SDARS licenses. The companies eventually become known XM Satellite Radio and Sirius Satellite Radio, respectively. Primosphere Limited Partnership and Digital Satellite Broadcasting Corporation are denied licenses by becoming third and fourth lowest bidders, respectively, during the auction.
2001 September 25: XM Satellite Radio officially launches.
2002 July 1: Sirius Satellite Radio officially launches.