Decoder Chips
Satellite radio took several years to develop and continues to be redefined and improved. Initially, engineers had to surmise beam satellite radio signals all the way from space, using a strong enough signal that could carry the many channels necessary. At one time, cost was prohibitive, but as time elapsed it became financially viable for Sirius and XM to develop such technology, thanks to the invention of chips that could decode the signals from space in a fairly energy efficient--and highly portable--manner.
Their Own Satellites
Both of the major satellite companies have their own satellites to beam their signals. Satellite TV and Internet systems, as well as satellites used by satellite radio stations such as XM, use geostationary satellites. Geostationary satellites feature fixed and, most importantly, inexpensive satellite antennas that allow for the proliferation of businesses offering services such as satellite radio, such as XM and Sirius. Also, geostationary satellites stay in geostationary orbit, meaning that from Earth it appears that these satellites are in fixed positions because they orbit the earth at the exact speed Earth is rotating.
Constant Signals
Due to the nature of geostationary spacecraft, ground units used to receive their signals are supposed to be free of obstacles such as buildings and possess a view of the southern sky to operate without interruptions. This wouldn't be possible without repeaters in large, urban areas placed by satellite companies so as to retransmit signals and ensure that radio reception is not interrupted even when the skyline may be obscured by human interferences.
Earthly Facilities
Each of the satellite radio providers has a facility with an extremely large storage system capable of holding a very large amount of songs and programming. XM's facilities in Washington reportedly have a storage capacity of 22 terabytes, 1 terabyte equaling 1,000 gigabytes. Programmers use a simple point-and-click routine to select the material they want to play, and then it is beamed down from the geostationary satellites high above Earth. However, digital compression does occur. Compression is used to limit the amount of bandwidth used, although the key is not to diminish audio quality. Once all of these factors are taken into consideration and applied, programming can be enjoyed in the home and on the go.
Tags: satellite radio, from space, geostationary satellites, satellite companies, signals from, signals from space, that could