How does satellite radio work?

Satellite radio is one of the biggest improvements in broadcasting since the

introduction of FM. Satellite radio signal can be broadcasted for more than
35,000 kilometers (22,000 miles) with complete clarity and high quality sound.
You will never get static interferences while listening to over 100 radio
channels. The idea behind satellite radio has appeared in 1992, when the United
States Federal Communications Commission granted a spectrum of the S band (the
2.3 GHz frequency) for Digital Audio Radio Service. The license to broadcast in
that band was allocated to Sirius Satellite Radio and XM Satellite Radio in
1997. Now there are three companies that provide satellite radio in the world:
Sirius and XM in Northern America and WorldSpace in Asia, Europe and Africa.



Each of these companies offer different broadcasting systems, since the radio
signal of each is proprietary. This means that you will have to buy different
hardware depending on your subscription to one of these companies. However,
there are three components common to all satellite radio services: the
satellites, the ground repeaters and the radio receivers. Different satellite
radio companies broadcast the radio signal in different ways. For instance, XM
satellite radio uses geostationary satellites which have orbits that are
synchronized with the movement of Earth. These satellites are located above the
equator. In order to allow subscribers to receive crystal-clear signal despite
obstacles such as buildings, hills or bridges, XM satellite radio service has
installed a network of repeaters antennas that receive the radio signal from the
satellites and retransmit it to the subscriber’s receiver Sirius, on the other
hand, uses satellites that have unique elliptical orbits around Earth. These
kinds of orbits allow satellites to get higher in the sky than geostationary
satellites and this prevents loss of signal. This is the reason why Sirius has
fewer terrestrial repeaters than XM.



Satellite radio services have digital broadcast centers where a huge amount of
music in digital format as well as CD format is stored. Radio programmers have
the task of selecting which song has to be played at which time. There are also
a lot of studios managed by digital radio companies where artists perform live.
All songs and material are transmitted to the satellites in digital format so
that the signal contains very high quality sound. The signal is encoded by the
satellite and then retransmitted to the repeaters antennas, which then transmit
it to the radio receiver which decodes it and plays the sound. The entire
process is very quick and reliable. Satellite radio would not be possible
without digital compression. Digital compression is a technique that uses
sophisticated algorithms to compress as much material as possible on the
available bandwidth. Once you make a subscription to a satellite radio provider
you will need the appropriate radio equipment. Traditional radios cannot decode
the signal received from satellites so you will need special equipment.



The popularity of satellite radio has exploded due to many technological
advancements that enabled manufacturers to offer the receivers at very
attractive prices. The fact that satellite radio is commercial free for many of
its channels is also a major selling point.