Satellite Radio - It's Not Your Father's Sputnik
By Albert Medinas
Ever wonder how this whole satellite radio
thing works? I mean, it seems to be THE thing
now. Many auto manufacturers are installing
satellite radio receivers in their new automobiles,
and there are home and portable models available
through your favorite electronics outlet.
But what is it? How does it work? Why should
I pay for radio?
You pay for TV, don’t you?
Once, in those long gone days of yore,
cable television operators offered us
television, which we had happily been
receiving for free through big tree-branchy
things on our roofs, for a fee. Many people
scoffed at the idea of paying for 30 channels
when they received four or five, gratis.
Well, just look at us now - cable TV,
satellite TV, 500 channels not quite filling
us up. So let’s stop asking questions
about why you should pay for satellite
radio, and let’s find out how the dern
thing works.
Well, how does the dern thing work?
Let’s start by looking at the type of
radio you are used to. AM radio broadcasts
at a frequency range from 535 kilohertz
(kHz) to 1700 kilohertz (1.7 MHz). FM
broadcasts between 88 MHz to 108 MHz.
Without getting too technical, one hertz
is basically one cycle per second. So
FM radio waves transmitted at 88MHz are
cycling 88 million times per second. This
seems like a lot, but is actually relatively
slow. Slower cycles require larger antennas
to transmit and to receive them. Also,
radio station antennas are stationary
and earthbound, and are therefore limited
in range. At higher cycles, smaller antennas
suffice. Cell phones range from 824 MHz
to 1990 MHz (1.99GHz), depending on the
type of service; this is a much faster
cycle, and therefore a smaller antenna
is used. Satellite radio is broadcast
at 2.3 GHz, so your car or portable receiver
has no trouble picking up the signal.
There have also been great advances in
antenna technology, which provide us with
a relatively small, flat antenna rather
than a dish that would have to be constantly
adjusted to point toward the satellite
as we drove around town picking up kids
from soccer practice.
All them numbers hertz my brain.
Let’s lay megahertz and gigahertz aside
for a moment. In addition to those higher
frequencies, satellite radio signals come
from, you guessed it, satellites. These
satellites are in a geosynchronous orbit,
which is an orbit that keeps the satellite
always above one location on the planet,
making it stationary relative to the earth.
The satellite receives a digital signal
from the ground station and bounces it
back to us. Because the signal is digital,
it can be compressed and beamed out packed
full of additional data (disguised as
0’s and 1’s), and received by any satellite
radio receiver tuned to the signal. Satellite
radio receivers can pick up the broadcast
from anywhere in the coverage area (meaning
the whole US) because the satellite is
orbiting at about 22,200 miles (35,000
km) above the earth, which allows for
a greater dispersion of the signal. It’s
analogous to water flowing from a showerhead.
An inch from the showerhead, the water
is a relatively tight stream. At the other
end of the shower, the water sprays all
over the wall, and gets on the bathroom
floor, causing your wife to yell angrily
about the mess. Satellite radio beams
work in much the same way. The radio signal
is much more widely dispersed 22,000 miles
from the satellite that sent the signal.
So with satellite radio, you can listen
to the same station as you drive from
New York City to Los Angeles, whereas
traditional radio has a range of only
about 30 to 40 miles. And thanks to repeaters,
or signal boosters, placed in urban areas,
you can receive generally uninterrupted
signals even driving through cities with
large buildings and thick bridges.
Hey, that’s kind of cool!
But wait! There’s much, much more! The
digital signal can carry much larger packets
of data, and satellite radios are equipped
with chipsets, or processors, that can
decode that data. So satellite radios
not only play the music, but also decode
and display information containing the
song title, album, artist, and genre.
Satellite radio owners can also choose
from hundreds of stations, which allows
for specialization, just like your cable
or satellite TV. In the same manner that
you can get the HBO Comedy Hits of the
Brahman Caste of Nepal Channel, and Tasmanian
Worm Wrestling on ESPN 127, you can receive
niche music, comedy, news, and sports
broadcasts on your satellite radio. Pick
your genre: any decade since the 40’s,
Rock, Country, Urban, Jazz, Blues, Dance,
Latin, World Music (e.g. Chinese, Indian,
African), Classical, Kids, and even news,
sports, comedy, and talk. You can also
tune in to any sub-genre of the above;
for example, in the Rock category you
can listen to soft, heavy, classic, deep
cuts, acoustic, instrumental, and even
unsigned acts.
Maybe I should get me one of them there
satellite radios.
Now that you know how it works, you can
listen for the sheer pleasure of it -
without all those nagging technical questions
churning in the back of your mind. Go
get you one.
Albert Medinas has developed and maintains
the website Satellite Radio Galaxy, which
answers the most common questions people
have about Satellite Radio. Please visit
us at http://www.satelliteradiogalaxy.com
today.
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