Satellite Digital Audio Radio service(SDARS)

SDAR is a satellite-based direct-broadcast radio service in which
digitally encoded audio entertainment material is broadcast to
Earth-based receivers, either directly from an orbiting satellite, or from the satellite to
the receiver via a repeater station (This is a special case in which the receiver is in a
shielded location).

SDARS is a radio communication service through which audio
programming is digitally transmitted by one or more space stations directly to
fixed, mobile, and/or portable stations, and which may involve complementary
repeating terrestrial transmitters, telemetry, tracking and control facilities.
Through SDARS compact-disc quality audio is available because of digital transmition
is employed.

History of Satellite Radio:

Satellite radio is an idea over a decade long. In 1992, the U.S.
Federal Communications Commission (FCC) allocated a spectrum in the
"S" band (2.3 GHz) for nationwide broadcasting of satellite-based
Digital Audio Radio Service (DARS).

Only four companies applied for a
license to broadcast over that band. The FCC gave licenses
to two of these companies in 1997. CD Radio (now Sirius Satellite Radio) and
American Mobile Radio (now XM Satellite Radio) paid more than $80 million each
to use space in the S-band for digital satellite transmission. The first satellite based radio launched by XM on Sep 25, 2001, then followed by Sirius on July 1, 2002.

At this time, there are three space-based radio broadcasters:
Sirius Satellite Radio

XM Satellite Radio

WorldSpace Satellite Radio


Importance and significance of Satellite radio:

We all have our favorite radio stations that we preset into our car
radios, flipping between them as we drive to and from work, on errands
and around town. But when you travel too far away from the source station, the
signal breaks up and fades into static.

Most radio signals can only travel about 30
or 40 miles from their source. On long trips that find you passing through
different cities, you might have to change radio stations every hour or so as the signals fade in
and out.

Now, imagine a radio station that can broadcast its signal from more than 22,000 miles (35,000 km) away and then come through on your car radio with complete clarity. One could drive
nearly hundreds of kilometers without ever having to change the radio station! Not
only would you never hear static interfering with your favorite tunes, but also the
music would be interrupted by few or no commercials.

Satellite radio companies are comparing
the significance of their service to the impact that cable TV had on
television 30 years ago. Listeners won't be able to pick up local stations using
satellite radio services, but they will have access to hundreds of stations offering a
variety of music genres. Each company has a different plan for its broadcasting
system, but the systems do share similarities.

XM Satellite Radio, Sirius Satellite
Radio and WorldSpace satellite individually provides digital-audio
radio services (SDARS), with commercial-free programming, digital-audio quality, and
countrywide coverage.

Each company offers nearly 100 channels of digital music and
talk radio (many of them commercial-free or with a reduced number of commercials)
that can be received from coast to coast with no service interruption. Each
offering number of music channels, these services clearly provides programming options
not available through traditional radio.

One of the main feature of SDARS is SDARS provides almost Commercial free (or Commercials are restricted) programs. And also it provides news, weather forecasts, and sports apart from
entertainment-based programs The primary application for this service is constant coast-to-coast coverage of radio for cars. We have all experienced the problem of trying to listen to radio on a long trip. Both AM and FM stations fade in and out as we drive into and out of their coverage
area. Portable full satellite radio service available now a days for
the car, home stereo and personal radio environments. Car manufacturers have been installing satellite radio receivers in some models for a few years now, and
several models of portable satellite radio receivers are available from a variety of
electronics companies.

Signal reception is generally poor as well as variable in the cases of AM or FM. With the SDARS systems, radio coverage throughout the 48 continental states is solid and continuous. Unlike
for AM and FM channels SDARS signals are available in a unique format

Subscription based radio service:

Because the technology requires access to a commercial satellite for
signal propagation; Satellite Radio services are commercial business
entities (not private parties), which offer a package of channels as part of their service
--requiring a subscription from end users to access its channels. Satellite
Radio Service can be subscribed at a monthly fee of $12.95 U.S. and up which
is very much worth full to the service that it gives.

Future of Satellite radio:

SDARS seems to get good market growth because of the following factors. Increasing
partnerships of XM and Sirius with Automobile OEM and distribution outlets made the
SDARS more popular. Introduction of more convenient hardware smaller and more
portable radios for the automobile as well as the home stereo,
computer and office and personal environments made possible at the
same time.