What happens when you take your antenna to outer space? You get a cell that covers an area hundreds of kilometers wide, and the whole world becomes your cellular network. This is precisely what the Iridium project did, when 66 satellites were launched into orbit with the hope of creating a mobile network that would reach every corner of the globe. It didn't catch as well as they'd hoped, though because the signal from a satellite did reach all corners of the globe, but only outdoors. Inside a building, the signal quality took a severe hit.

Iridium satellites, however, still orbit the earth and are used by other companies to provide satellite telephone services.

How Satellite Phone Call Works
A satellite constellation consists of many Low Earth Orbiting (LEO) satellites. When you switch on your satellite phone, it sends a signal straight up to the nearest satellite. The satellite then relays this signal to the nearest Land Earth Station (LES), registering you with the constellation. If you are calling someone at the other end of the world, your signal will be bounced off many satellites in the constellation before it is beamed down to the recipient.

Satellite phone service offers common Internet services through their own gateways and outgoing servers, which is goog because one doesn't have to deal with the eccentricities of Internet access via cell phones - slow, sometimes unstable even as connections depend on network traffic.

Nearly all companies that offer satellite phone services offer dual-mode phones - they can switch between satellite and GSM networks. The customer then doesn't have to bear the high cost of satellite telephony when in an area well-covered by a GSM network.



This post has been edited by amitbhandari: Apr 30 2006, 04:22 AM

My dad uses a satellite phone to call me up, time to time, from guess what. The Sahara Desert. They are pretty cool devices, but signal acoustics should be improved if this is something that will be taking mass appeal. I can say that Satellite signals aren't much to talk about.

only problem with sat phones they are very expensive to use 1 minute of phone time would cost $8-$10. Of course Yeah you have to be out doors with a clear sky on both sides of the world to get a clear signal.