XM Satellite Radio

XM Satellite Radio is one of two satellite radio services available in the United States and Canada. It is a subsidiary of Sirius XM Radio and provides a pay-for-play service similar to satellite television. Its service includes 73 different music channels, 39 news, sports, talk and entertainment channels, 21 regional traffic and weather channels and 23 play-by-play sports channels. The Company originated in 1988 with the formation of the American Mobile Satellite Corporation, originally dedicated to satellite broadcasting of telephone, fax, and data signals. In 1992, AMSC established the American Mobile Radio Corporation which later became XM Satellite Radio Holdings, Inc. The satellite radio service, as we know it today, was launched on September 25, 2001.


Satellite radio
XM's primary business is satellite radio entertainment.XM provides music, news (both simulcast and syndicated programming), sports, talk radio, comedy (both stand-up and radio shows), and even radio drama. In addition, XM broadcasts local weather and traffic conditions in its larger markets.
To get this service a custumer would need to buy a reciever in order to recieve the satellite radio programming. Reciever prices rangs from $50 to well over $200. After obtaining a reciever a custumer would then need to subscribe to XM radio services in order to get the various channels offered to XM radio subcribers. Subscribtion prices began at a basic deal price of $12,95/month
XM also offers music downloads through XM+Napster for Windows users. This service is being integrated with XM Online and the new MP3 capable XM receivers, such as the Pioneer Inno or the Samsung Helix.
Several music channels of XM radio can also be received on the DirecTV or Dish Network satellite networks. To listen to XM on DirecTV or Dish Network, no XM subscription is required, but you must have a Dish Network or DirecTV subscription.


XM Radio Online
XM's Internet radio product, offers many of XM's music stations and can be accessed from any Internet connected Windows or Macintosh computer, or via the iPhone/iPod Touch SIRIUS XM app. It used to be included with XM Radio subscriptions before March 11, 2009, or was available separately for US$7.99 a month to Internet-only subscribers. It is now available as an add-on ($2.99) or alone ($12.99).


Weather and traffic

XM also provides data services such as weather information for pilots and weather spotters through its XM WX Satellite Weather datacasting service. This up to the minute weather information can be displayed in the cockpit of an aircraft equipped with a satellite weather receiver.
XM also has dedicated traffic and weather channels that cover many major metropolitan areas. These channels play a continuous loop of local weather information and detailed traffic data.

How it Works

XM Radio is satellite radio. XM provides digital programming directly from three high-powered satellites in geostationary orbit above the equator. XM-1 ("Roll") and XM-2 ("Rock") are co-located at 115° west longitude and XM-3 ("Rhythm") is located 85° west longitude in addition to a network of ground-based repeaters. These three satellites combine to make sure there is no interrupted coverage throughout all of North America.
A song at XM Radio starts its broadcast life by being recorded into a specific format on a storage medium. The DJ at each XM station then selects the track or album of tracks to play for the next 15 to 30 minutes, previews the music, and allows the control system to encode the original source music using the aacPlus Codec.
Each XM channel is handled by an encoder. Each encoder transmits the necessary digital files for each particular station to a multiplexer, where they are combined with the files from all additional XM channels. Once all of XM's channels are sent to the multiplexer, the massive digital stream is modulated onto an RF carrier, and transmitted on XM's section of the S-Band frequency (2332.5 to 2345.0 MHz) to one of XM's three satellites.
From one of the three satellites, the encoded signals are sent back to earth, and the antenna connected to your XM receiver picks up the frequency. Since your receiver will be the only thing decoding this signal, you can rest assured that compared to the many digital transmissions that re-broadcast, re-store and re-encode the signal, the XM signal will never be sliced again.


XM Radio has many products available, ranging from dock and play radios to portables radios, and home products to in-vehicle products; even products for business. And just recently, they developed a software application allowing subscribers to play programming from their Apple iPhone and Apple iPod Touch devices. The software was available for download since June 17, 2009.

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