The world has come a long way since the early days of the 'Sputnik'! Satellite systems are now providing both voice and data communication for parts of the world where there is little or no land or cell phone provision. Using satellite telephones help you to keep in contact when you are in the air or out at sea. They also help us to track and remain in contact with adventurers who test the limits of endurance and skill. We are able to follow their routes, talk to them and receive images and movies from wherever they may be and we can be instantly ready to help them when things don't go quite according to the plan.

How Do Satellite Phones Work? - When you make a call from a satellite phone the signal is transmitted from the phone to one of a number of networked satellites in orbit overhead. The satellites in the network communicate with each other to find out which one of them is closest to the satellite phone on the other end of the link. When the route has been found then two-way transmission is routed accordingly. The snag with it all is that communications with the satellite has to be relatively obstruction free or the signal will be lost. Undesirable obstructions can even include bad weather so communications can't be relied upon all the time any time you want. To improve the quality of the link you should try to make the call outdoors or ensure that your phone is connected to a suitable outdoor antenna.

At the time of writing 5 major players provide satellite communications. The largest of these are Global Star and Iridium with Iridium being the biggest. Most people have probably heard of Iridium who has a network of 66 satellites in a low earth orbit and they have an additional 13 satellites spare which I find a little surprising. I guess these are for future expansion. You will find these satellites in orbit about 485 miles above the surface of the planet.

The providers supply satellite communications equipment to an extensive variety of markets including construction, leisure, mining, government and maritime. They also provide equipment to the armed forces and for rescue and disaster relief organisations. Companies tend to sell their many services through a collection of service partners, value-added resellers and manufacturers.

Wherever there is a need for good, reliable, work-anywhere communications you will find satellite phones in use. The military make use of them extensively, as do airlines and shipping. They can also be invaluable in areas where disaster has struck and it's likely that land based communications have been disrupted by the disaster or they never existed in the first place. Satellite phones can be easily tracked too. This can come in useful when guiding aircraft quickly into isolated areas.

Trucks travelling close to the Alaskan pipeline are being equipped with satellite phones to combat terrorism. If a truck gets hijacked then the satellite network notifies the authorities instantly. Using the satellite phone and the network, the hijacked truck can be disabled quickly and before the terrorists have a chance to use it as a weapon.

Satellite telephones are still an expensive form of communication, far more expensive than most calls from a cellular phone. The technology will continue to improve however and when the usage becomes more widespread, you should see the costs fall dramatically. At the time of writing call costs appear to be comparable with the cost of international roaming cell phone calls. As a public relations exercise and to give the consumer market a bit of a boost, the industry is currently engaged in fund raising with a view to supplying satellite phones and free calls to the US National Guard serving in Iraq.