Introduction to Satellite Digital Audio Radio service(SDARS)

Satellite Digital Audio Radio Serviceyour car radio with complete clarity. One could
(SDARS):SDAR is a satellite-baseddrive
direct-broadcast radio service in whichnearly hundreds of kilometers without ever
digitally encoded audio entertainment material ishaving to change the radio station! Not
broadcast toonly would you never hear static interfering with
Earth-based receivers, either directly from anyour favorite tunes, but also the
orbiting satellite, or from the satellite tomusic would be interrupted by few or no
the receiver via a repeater station (This is acommercials.Satellite radio companies are
special case in which the receiver is in acomparing
shielded location). SDARS is a radiothe significance of their service to the impact
communication service through which audiothat cable TV had on
programming is digitally transmitted by one ortelevision 30 years ago. Listeners won't be able
more space stations directly toto pick up local stations using
fixed, mobile, and/or portable stations, and whichsatellite radio services, but they will have access
may involve complementaryto hundreds of stations offering a
repeating terrestrial transmitters, telemetry,variety of music genres. Each company has a
tracking and control facilities.different plan for its broadcasting
Through SDARS compact-disc quality audio issystem, but the systems do share similarities.XM
available because of digital transmitionSatellite Radio, Sirius Satellite
is employed.History of Satellite Radio:SatelliteRadio and WorldSpace satellite individually
radio is an idea over a decade long. In 1992, theprovides digital-audio
U.S.radio services (SDARS), with commercial-free
Federal Communications Commission (FCC)programming, digital-audio quality, and
allocated a spectrum in thecountrywide coverage. Each company offers
"S" band (2.3 GHz) for nationwide broadcasting ofnearly 100 channels of digital music and
satellite-basedtalk radio (many of them commercial-free or
Digital Audio Radio Service (DARS). Only fourwith a reduced number of commercials)
companies applied for athat can be received from coast to coast with
license to broadcast over that band. The FCCno service interruption. Each
gave licensesoffering number of music channels, these
to two of these companies in 1997. CD Radioservices clearly provides programming options
(now Sirius Satellite Radio) andnot available through traditional radio.One of the
American Mobile Radio (now XM Satellite Radio)main feature of SDARS is SDARS provides
paid more than $80 million eachalmost Commercial free (or Commercials are
to use space in the S-band for digital satelliterestricted) programs. And also it provides news,
transmission. The first satellite based radioweather forecasts, and sports apart from
launched by XM on Sep 25, 2001, then followedentertainment-based programs The primary
by Sirius on July 1, 2002. At this time, there areapplication for this service is constant
three space-based radio broadcasters:coast-to-coast coverage of radio for cars. We
Sirius Satellite RadioXM Satellitehave all experienced the problem of trying to
RadioWorldSpace Satellite Radio Importance andlisten to radio on a long trip. Both AM and FM
significance of Satellite radio:We all have ourstations fade in and out as we drive into and out
favorite radio stations that we preset into our carof their coverage
radios, flipping between them as we drive to andarea. Portable full satellite radio service available
from work, on errandsnow a days for
and around town. But when you travel too farthe car, home stereo and personal radio
away from the source station, theenvironments. Car manufacturers have been
signal breaks up and fades into static. Most radioinstalling satellite radio receivers in some models
signals can only travel about 30for a few years now, and
or 40 miles from their source. On long trips thatseveral models of portable satellite radio
find you passing throughreceivers are available from a variety of
different cities, you might have to change radioelectronics companies.Signal reception is generally
stations every hour or so as the signals fade inpoor as well as variable in the cases of AM or FM.
and out. Now, imagine a radio station that canWith the SDARS systems, radio coverage
broadcast its signal from more than 22,000 milesthroughout the 48 continental states is solid and
(35,000 km) away and then come through oncontinuous.