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Joined: Dec 2008
21-09-2008, 11:39 AM
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 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 kill) away and then come through on your car radio with complete clarity without ever having to change the radio station.
Satellite Radio or Digital Audio Radio Service (DARS) is a subscriber based radio service that is broadcast directly from satellites. Subscribers will be able to receive up to100 radio channels featuring Compact Disk digital quality music, news, weather, sports. talk radio and other entertainment channels.
Satellite radio is an idea nearly 10 years in the making. 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).. In 1997. the FCC awarded 8-year radio broadcast licenses to two companies, Sirius Satellite Radio former (CD Radio) and XM Satellite Radio (former American Mobile Radio). Both companies have been working aggressively to be prepared to offer their radio services to the public by the end of 2000. It is expected that automotive radios would be the largest application of Satellite Radio.
The satellite era began in September 2001 when XM launched in selected markets. followed by full nationwide service in November. Sirius lagged slightly, with a gradual rollout beginning _n February, including a quiet launch in the Bay Area on June 15. The nationwide launch comes July 1.
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Active In SP
Joined: Jun 2010
28-09-2010, 03:04 PM
Satellites have been a highly effective platform for multiform broadcasts. This has led to a revival of the radio era.The satellite radio is a natural choice to bridge the digitalgap. It has several novel features like selective addressing and error control. The value-added services from such systems are of particular interest.
Man has always been fascinated by the ‘heavenly voices’ from the skies. This fascination has manifested itself in many mythologies where he has received divine messages, warnings, and forecasts from the heavens. It was this undiminished fascination that kept him working towards the radio system. It was one hundred years ago that Marconi first transmitted the letter ‘S’ across the Atlantic Ocean. At that time, conveying information across such large distances was not as much a novelty as the new concept of broadcasting. While telegraphy was constrained by physical network of lines, radio reached a widespread, unidentified audience. With the evolution of technology, today, man-made satellites placed up in the skies are able to deliver not just messages but crystal-clear music and news directly to the listeners separated by huge geographical distances. The reception of these programmes on ground is possible using special satellite signal receivers.
Joined: Apr 2012
26-04-2012, 11:53 AM
Jan2002p47-52.pdf (Size: 58.18 KB / Downloads: 52)
Man has always been fascinated by the ‘heavenly voices’ from
the skies. This fascination has manifested itself in many mythologies
where he has received divine messages, warnings, and
forecasts from the heavens. It was this undiminished fascination
that kept him working towards the radio system. It was one
hundred years ago that Marconi first transmitted the letter ‘S’
across the Atlantic Ocean. At that time, conveying information
across such large distances was not as much a novelty as the new
concept of broadcasting. While telegraphy was constrained by
physical network of lines, radio reached a widespread, unidentified
A satellite’s orbit is decided depending on the application. The
geo-stationary orbit (GSO) is considered ideal for broadcast
purposes. It is advantageous because of the ease of tracking – or
rather the lack of tracking. In GSO, even though a satellite
moves at a speed of over 10,000 km per hour, it appears to hang
perfectly motionless in the sky.
Modulation is the way information is imparted to the electromagnetic
signal that is referred to as the carrier wave. In
amplitude modulation (AM), the amplitude of the radio frequency
(RF) carrier is made to vary in accordance with the audio
waveform. It is obvious that in this mode, it would be quite
sensitive to additive electrical noise. Frequency modulation
FM has a much better noise immunity, as it is the frequency of
the carrier wave that is varied in a small range according to the
audio waveform. However, noise free reception does not necessarily
mean high fidelity (HiFi).
Because of the tremendous advancement in digital technology
in the recent years satellite radio is fully digital. In a digital
radio, the transmitter processes sounds into patterns of binary
digits and at the listening end, the digital radio reproduces the
sound from the digits. By using techniques of forward error
control, it is possible to make the reception virtually immune to
Joined: Apr 2012
31-05-2012, 12:25 PM
Satellite Radio.ppt (Size: 95.5 KB / Downloads: 67)
What Is Satellite Radio?
Satellite Radio is digital radio that receives signals from a broadcast communication satellite.
Functions any place there is a line of sight between the antenna and the satellite
Requires access to a commercial satellite for signal propagation.
Services are a commercial business entity that offers packages of channels as part of service
Requires a subscription from end users.
Sirius Satellite Radio
Operated in the United States and Canada
Provides 69 channels of music
65 channels of news, sports and entertainment
Broadcast 24 hours a day commercial free from three satellites
$12.95/mo+ $10-$15 activation
6.024 listeners as of Jan.
Based in Silver Spring,MD
First stated by wanting to improve literacy in Africa
Covers Asia, Europe, and Africa
Licensed to serve Central and South America
AfriStar (serves Africa) and AsiaStar (serves Asia and Europe)
3 transmission beams; 50 channels each.
XM Satellite Radio
United States and Canada
73 music, 39 news, sports and entertainment, 29 regional traffic and weather, 23 play-by-play sports.
$12.95/mon, $7.99 internet only
Provides weather to pilots through XM WX satellite Weather data casting service.
Satellite Radio vs. Others
Monthy Fees –SR $12.95+
Listening availability- SR very high, others are moderate to low
Sound Quality-SR high, AM=very low, FM=High
Variety-SR Highest, Variable due to economic factors
Government Regulation SR low to none, others significantly regulated.
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