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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."
PS the article says texts are "40 cents each, only four times the piece rate for cell phone." That's way too much, just as 10 cents for a regular text is a complete ripoff. 40 cents each works out to around $3000/MB, whereas (non-texting) satellite data on the same phone costs $5/MB. It really makes me wonder how they come up with these prices.
Because people pay it.
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.
Irridium has the advantage of being in low earth orbit versus Direcway's geosynchronous orbit. The path loss between a 250ish mile orbit and a 22,500 mile orbit is a hefty number of dB.
Assuming both systems At 2Ghz, it is 150dB at 250 miles and 190db at 22,500 miles. That 40db difference either has to be made up in raw transmit power at both ends or by using a 5.3m dish antenna.
At the prices they pay for service, it might just make sense for them to buy out Iridium.
Essentially, they did. When Iridium was about to go under and the satellites were days from being de-orbited, DoD bought into the system at a bargain price. This turned out to be extremely useful once the US got entangled in Iraq and Afghanistan. Originally, DoD bought unlimited airtime for 10,000 users. Now they're past 100,000 DoD users. Iridium overall has about 360,000 users.
It's the thing to have if you need to communicate from Outer Nowhere. Works anywhere on the planet that you can see the sky. Airtime is about $1 to $2 a minute, and phones are about $1500. A roll-up solar panel is a common accessory. The typical user drives a HUMMV, a yacht, or a dogsled.