-70C is a bit pushing the envelope. The coldest temperatured in record has been in Vostok, antartice and that was -89.2C. So antarctic is one possible place for it, and it wouldnt surpirce me mutch if there were a gsm base stations in some of the expedition stations. The gsm can't be farther than about 30km from base station as that is the limit in the travel delay factor coded to the signal so you would have to stay fairly close to base station. You cant get past that limit with power or antennas.
Next possible place is Siberia where the temperature goes often close to -70C. In Canada the records are about -55C so not as cold as siberia. Both Canada and Siberia might have some coverage on mountains.
There are several problems with getting a phone working in those temperatures.
First batteries. Lithium and NiMH both work badly in cold, NiCd a bit better but not close enough in that temperature. Even lead-acid has trouble below -40. Sodium-hyroxide battery might work but dont think theres ever made one for that size.
Display. No LCD display works that low, even -20 makes them sluggish. Need to be led or electroluminence. Even them start to have trouble at those temperatures. Plasma would work best but kind of bulky for that use.
Transistors. Even them start to have trouble that low. Bias point changes with temperature and as there isnt that many uses for chips for extreme low temperatures all processors etc would have to be special made for this phone. Even the manufacturing process for these chips would have to be custom made.
Easiest way to do this, replace the regular battery with plutonium one. Works in cold temperatures and heats the electronics to working temperatures. Just have to make a temperature controlled cooling on it.
Register
Problems
-70C is a bit pushing the envelope. The coldest temperatured in record has been in Vostok, antartice and that was -89.2C. So antarctic is one possible place for it, and it wouldnt surpirce me mutch if there were a gsm base stations in some of the expedition stations. The gsm can't be farther than about 30km from base station as that is the limit in the travel delay factor coded to the signal so you would have to stay fairly close to base station. You cant get past that limit with power or antennas.
Next possible place is Siberia where the temperature goes often close to -70C. In Canada the records are about -55C so not as cold as siberia. Both Canada and Siberia might have some coverage on mountains.
There are several problems with getting a phone working in those temperatures.
First batteries. Lithium and NiMH both work badly in cold, NiCd a bit better but not close enough in that temperature. Even lead-acid has trouble below -40. Sodium-hyroxide battery might work but dont think theres ever made one for that size.
Display. No LCD display works that low, even -20 makes them sluggish. Need to be led or electroluminence. Even them start to have trouble at those temperatures. Plasma would work best but kind of bulky for that use.
Transistors. Even them start to have trouble that low. Bias point changes with temperature and as there isnt that many uses for chips for extreme low temperatures all processors etc would have to be special made for this phone. Even the manufacturing process for these chips would have to be custom made.
Easiest way to do this, replace the regular battery with plutonium one. Works in cold temperatures and heats the electronics to working temperatures. Just have to make a temperature controlled cooling on it.