I routinley carry a Hand Held Satellite phone as part of my Survival Kit . I find that as I do a lot of charter flights outside of Mobile phone range ( you call them Cell phones ), within and outside Australia, carrying a Sat phone was a plus ( mine has international roaming as part of it's features ) . As I also carry a very good hand held GPS receiver, that and the Sat phone are an excellent back up to the GPS enabled 406 Mhz PLB, which is also carried as part of my 4 person Survival kit. My kit also carries a Mobile phone, apart from the one that I carry on my person, as well as a hand held aircraft radio, and a hand held UHF CB radio. My kit as I said is based around equippiing 4 people for 3 days ( tools/shelter/food,cooking / signalling / protection). The protection component includes a 9MM Hand gun, but thats another story.