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How Satellite Phones Work

 
 

Satellite Phones > How Satellite Phones Work

 
phone, satellite, and telecommunications tower It seems like not that long ago when you wanted to use the phone, your were relegated to your home, office, or other place where there was a landline.  No longer.  With the advent of cell phones, people have learned they can communicate anytime, anywhere.  Unless, of course, they are in a spot where there isn't a cell phone tower.  What then?  When it comes to the most comprehensive global coverage, consider the satellite phone.

Satellite phones are more expensive to buy and operate than cellular phones.  They are considerably more bulky and don't work indoors without an external antenna.  But if you are frequently in areas where cellular phone service isn't available, a satellite phone is a terrific option for staying mobile and in touch.

How do satellite phones work?  Just like cellular phones, satellite phones use radio waves to send their signal.  Because satellite phones use satellite signals, the antenna is a little larger, and they must be used in an area where there is unobstructed sky.  Surprisingly, satellite phone services have been available for more than 25 years.  There are several different types of satellite phone services, but the most important difference is whether the service uses low earth orbit (LEO) satellites or geosynchronous — sometimes called geostationary — satellites.

LEO Satellites

LEO satellites, which are in lower orbit, move relative to the earth's surface.  Heights of LEO satellites vary greatly.  LEO orbits can be polar, which means that they circle around each pole.  Satellites that do not orbit each pole don't reach the Arctic and Antarctic regions, which are the highest and lowest reaches of the earth.  The lower orbit a satellite has, the less coverage it has.  So you need more LEO satellites in order to provide global coverage.  Satellite phones that use LEO satellites have an unnoticeable delay, and the phones are more portable because they don't need to send or receive a signal from a very great distance.

Geosynchronous Satellites

These satellites, which are at a fixed height of 22,300 miles above the earth, rotate around the earth at the same speed as the earth.  Because of this, the satellite appears to be stationary.  One satellite can cover about a third of the earth's surface.  However, some of them have directional antennas that limit the service areas.  Because the signal has to be sent so far, satellite phones that use geosynchronous satellites have fairly noticeable response delays.

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