I recently bought an Inmarsat IsatPhone Pro satellite telephone. I had set some requirements for a satellite phone ("satphone") , including true worldwide operation, good reliability, and reasonable price, and the IsatPhone Pro (introduced in 2010) was not just the best deal, but the only phone that met all my my requirements. I shopped around for a few months and eventually bought the IsatPhone Pro Emergency Kit from GMPCS, a Florida-based retailer.
This kit is priced at $821. It includes the phone (normally around $600 from online sellers), one year of "Emergency" service priced at $150/year with 60 minutes of airtime, an extra battery, AC and DC chargers, a Pelican flashlight, and an orange Pelican 1200 case. (I swapped out the Pelican flashlight for a smaller and much brighter Fenix light instead.)
This represents a good price for the phone and accessories, but the service is actually the best part of the deal since there are few if any other ways to get satellite phone service for such a low annual price. Globalstar's minimum plan is $360/year and Iridium starts at $225/year; both of these rates include no airtime.
Additional airtime for all satphone services usually runs around a dollar a minute. It costs less if you have a high-priced plan and more for the cheaper plans ($1.39 for extra minutes on Inmarsat's emergency plan, for example). That's just for the airtime; customers pay separately for outbound calls, and callers pay hefty long-distance fees for calls to the satphone. If you think you may end up using a satphone regularly (for example, if you expect to use it from a retreat home where cell phone service isn't available), you'd better make sure you can afford it.
(By comparison, though, the cost for the kit plus a second year of service is about $600 less than the minimum cost of an iPhone 4 with a two-year AT&T service contract, so it isn't totally outrageous.)
Physically, the IsatPhone Pro is much larger than any current cell phone, about 6.7" long by 2.1" wide and 1.5" thick. Even so, it's smaller than many older satphones. This size is due in part to the large antenna, which pivots out from the side of the phone and must be aimed roughly at the satellite.
This brings us to the other big difference between Inmarsat and the other two satphone services available in the US (Iridium and Globalstar). Inmarsat's satellites are in geosynchronous orbit, their positions fixed for any location on the ground. Generally speaking, if you can see the sky, you can communicate. Only three satellites are required for global coverage, at least roughly between the Arctic and Antarctic Circles. Those living in Alaska, Greenland, and extreme northern Russia should review the coverage maps.
The Iridium and Globalstar networks have many more satellites, but they're in low Earth orbit. Those networks can be unavailable from time to time because the satellites are out of view, and even if you're able to establish a call, it may be cut off because each satellite is only visible for 10-15 minutes at a time.
The IsatPhone Pro requires a GPS fix in order to operate, but the GPS receiver seems to be reasonably sensitive; whenever the phone could see the Inmarsat satellite, it could see the GPS satellites too. The phone has a convenient "send GPS location" feature that creates a text or e-mail message with your coordinates.
I have spent a lot of time fiddling with my IsatPhone Pro, but not a lot of time making calls. I have found that it always gets a reliable signal from here in California, which is what I expected given that the northern portion of the satellite's coverage area is pretty much centered on North America.
Although Inmarsat states quite clearly that the IsatPhone Pro will not work indoors, I actually found that my phone can get a usable signal right through the roof of my timber-framed, asphalt-shingled house, though some places in the house seem to work much better than others for no obvious reason. This suggests that it may sometimes work even under tree cover, but it definitely won't work through the metal roof of a car.
Outdoors, I've had no trouble making or receiving calls to land line and cellular phones, and call quality is very good. Because the phone has a speakerphone capability built in as well as Bluetooth headset support, it's easy to leave the phone in a fixed position (ideally, resting on its side with the folding antenna aimed at the satellite) during the call.
The e-mail service built into the phone, though limited, also works well. Messages go through quickly, but the key limitation is that e-mails sent directly to the phone (email@example.com) are limited to 160 characters. e-mails sent from the phone can be up to 1,600 characters.
Interestingly, text (SMS) messages can be 1,600 characters both ways, but Inmarsat does not have SMS service agreements in place with all US cell phone carriers. The result is a confusing patchwork of interoperability. The IsatPhone Pro can send text messages to AT&T cell phones, but an AT&T cell phone can't send texts to the IsatPhone Pro. T-Mobile phones work normally in both directions. I haven't tested a Sprint PCS phone.
These limits on e-mail and text operation are weird, but not a problem for the way I intend to use the phone, which will be limited to those hopefully nonexistent emergency situations when my cell phone isn't working and I can't raise anyone on my amateur radio. I figure it'll be enough to place a call to a friend or relative as needed, perhaps augmented by a text or e-mail message with my coordinates. Emergency services are another option; Inmarsat says it supports calls to 911 and 112 (the European equivalent of 911), though I don't know exactly where such calls go.
The final feature worth noting here is that the IsatPhone Pro can be connected to a computer via USB and act as a data modem to access Internet services. The speed is very low (2,400 bits per second uncompressed, up to 20 kbps compressed) and data transfers cost $6.50 per megabyte (after compression, if any), but this option allows normal e-mail and Web access when necessary. Windows, Mac, and Linux systems are supported.
All in all, I'm very satisfied with this purchase. The up-front, annual, and per-call costs are significant, but the IsatPhone Pro provides a capability that can't be matched by any other communication method. I recommend it for those who have the rest of their preps in order.