| Satellite Digital Audio Radio Service | | | | your car radio with complete clarity. One could |
| (SDARS):SDAR is a satellite-based | | | | drive |
| direct-broadcast radio service in which | | | | nearly hundreds of kilometers without ever |
| digitally encoded audio entertainment material is | | | | having to change the radio station! Not |
| broadcast to | | | | only would you never hear static interfering with |
| Earth-based receivers, either directly from an | | | | your favorite tunes, but also the |
| orbiting satellite, or from the satellite to | | | | music would be interrupted by few or no |
| the receiver via a repeater station (This is a | | | | commercials.Satellite radio companies are |
| special case in which the receiver is in a | | | | comparing |
| shielded location). SDARS is a radio | | | | the significance of their service to the impact |
| communication service through which audio | | | | that cable TV had on |
| programming is digitally transmitted by one or | | | | television 30 years ago. Listeners won't be able |
| more space stations directly to | | | | to pick up local stations using |
| fixed, mobile, and/or portable stations, and which | | | | satellite radio services, but they will have access |
| may involve complementary | | | | to 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 is | | | | system, but the systems do share similarities.XM |
| available because of digital transmition | | | | Satellite Radio, Sirius Satellite |
| is employed.History of Satellite Radio:Satellite | | | | Radio and WorldSpace satellite individually |
| radio is an idea over a decade long. In 1992, the | | | | provides digital-audio |
| U.S. | | | | radio services (SDARS), with commercial-free |
| Federal Communications Commission (FCC) | | | | programming, digital-audio quality, and |
| allocated a spectrum in the | | | | countrywide coverage. Each company offers |
| "S" band (2.3 GHz) for nationwide broadcasting of | | | | nearly 100 channels of digital music and |
| satellite-based | | | | talk radio (many of them commercial-free or |
| Digital Audio Radio Service (DARS). Only four | | | | with a reduced number of commercials) |
| companies applied for a | | | | that can be received from coast to coast with |
| license to broadcast over that band. The FCC | | | | no service interruption. Each |
| gave licenses | | | | offering number of music channels, these |
| to two of these companies in 1997. CD Radio | | | | services clearly provides programming options |
| (now Sirius Satellite Radio) and | | | | not 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 each | | | | almost Commercial free (or Commercials are |
| to use space in the S-band for digital satellite | | | | restricted) programs. And also it provides news, |
| transmission. The first satellite based radio | | | | weather forecasts, and sports apart from |
| launched by XM on Sep 25, 2001, then followed | | | | entertainment-based programs The primary |
| by Sirius on July 1, 2002. At this time, there are | | | | application for this service is constant |
| three space-based radio broadcasters: | | | | coast-to-coast coverage of radio for cars. We |
| Sirius Satellite RadioXM Satellite | | | | have all experienced the problem of trying to |
| RadioWorldSpace Satellite Radio Importance and | | | | listen to radio on a long trip. Both AM and FM |
| significance of Satellite radio:We all have our | | | | stations fade in and out as we drive into and out |
| favorite radio stations that we preset into our car | | | | of their coverage |
| radios, flipping between them as we drive to and | | | | area. Portable full satellite radio service available |
| from work, on errands | | | | now a days for |
| and around town. But when you travel too far | | | | the car, home stereo and personal radio |
| away from the source station, the | | | | environments. Car manufacturers have been |
| signal breaks up and fades into static. Most radio | | | | installing satellite radio receivers in some models |
| signals can only travel about 30 | | | | for a few years now, and |
| or 40 miles from their source. On long trips that | | | | several models of portable satellite radio |
| find you passing through | | | | receivers are available from a variety of |
| different cities, you might have to change radio | | | | electronics companies.Signal reception is generally |
| stations every hour or so as the signals fade in | | | | poor as well as variable in the cases of AM or FM. |
| and out. Now, imagine a radio station that can | | | | With the SDARS systems, radio coverage |
| broadcast its signal from more than 22,000 miles | | | | throughout the 48 continental states is solid and |
| (35,000 km) away and then come through on | | | | continuous. |