sattelite phones

[kileh]

Does anyone know if sattelite phones could still function without support from the ground? If so for how long? I know they are expensive so I don't plan on getting one but would it be something worth looking for if there was a complete and permanent loss of the power grid?

[TacAir]

The ground control stations have to have power to even make a call. No smarts are in space, it's all on the ground.

[raptor]

in addition to ground power you need ground phone lines working even if you are making a sat phone to sat phone call.

[Wesson357]

Iridium satellites are cross-linked in space so Iridium to Iridium calls do not rely on landlines.

[raptor]

Iridium satellites are cross-linked in space so Iridium to Iridium calls do not rely on landlines.

The LEO Iridium satellites do link to each other to route a call to the ground stations in Tempe, AZ and Hawaii. However even if you are making an Iridum to Iridium call these have to be routed at one of the the ground stations and then back to the phone. Thus no power at both of these stations means even Iridum to Iridum calls will not go through.

BTW Iridum is excellent and I use them on many occasions. They work worldwide.

[Wesson357]

A lot of the information out there suggest that ground stations are not required.

This system uses cross-link technology, a unique technology that provides redundancy by allowing satellites to talk to each other. Therefore, when placing an Iridium-to-Iridium call, a user never depends on landlines - ideal for emergency management situations when infrastructures are not reliable. With optimal conditions (line of sight), Iridium has 99.8% call completion.

link

These downlinks are primarily used for calls that need to be routed into the terrestrial phone system. For satellite phone to satellite phone calls, it is possible to route the traffic directly through space with no downlink. Although the satellite to satellite routing and the associated downlinks add a considerable degree of complexity to the Iridium system, it does enable fewer earth stations to be required, and it also enables full global coverage to be provided.

link

The Iridium network call process is different than the Globalstar network. Unlike Globalstar where all the switches and most of the call handling is made from the ground station... most of the switching and call handling is made by the Iridium satellites themselves. Iridium to Iridium calls are handled in this way, calls will go up to the Iridium satellite then may travel from Iridium satellite to Iridium satellite till it reaches the receiving Iridium satellite phone never using the Iridium ground station or the public phone network. With this type of call the Iridium constellation completely handles the call.

link

[raptor]

Hmm... I could be wrong here but I though that this feature would be available only when the Iridium NEXT constellation was operational. Note the quote indicates that this WILL be possible. I know they offer reduced rates for these calls. I also know the DOD iridium system added push to talk and other functions.

Each Iridium NEXT satellite will be cross-linked to four other satellites - two in the same orbital plane and one in each adjacent plane. These links will create a dynamic network in space. Traffic will be routed among Iridium satellites without touching the ground, ensuring a reliable connection. Iridium NEXT satellites will be virtually impervious to natural disasters, including hurricanes, tsunamis and earthquakes, that can damage ground-based wireless towers and terrestrial wires.

http://www.iridium.com/About/IridiumNEX ... stellation

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