AT&T Introduces Satellite-Enabled Smart Phone
crimeandpunishment writes "Here's one way to deal with spotty cell phone coverage: backstop the network on a satellite. AT&T is now selling its first satellite-enabled smart phone....which could be invaluable for boaters, forest rangers, and others who regularly leave regular cellular coverage areas. But the TerreStar Genus comes with a hefty price tag: $799.....and the data costs are as sky-high as the satellite....400 times more than a standard plan. It also has to have a clear view of the southern sky, which means it can only be used outdoors."
The links just won't close. I don't have the exact numbers I'd need to do a link budget, but the Direcway links are engineered for a Ku link with a .9m dish on the ground and a 3-4m dish on the spacecraft, with the ground transmitting at 2-4 watts. The TerreStar satellite has an 18m dish on the satellite. That's a crapload more gain. TerreStar also uses a 2Ghz link which is also virtually unaffected by weather.
Also keep in mind that generating sufficient output power at Ku frequencies is extremely inefficient. A Direcway 4W BUC amplifier draws about 50 watts out of its power supply. I doubt your average cell phone's battery can tolerate that.