When writing books about the apocalypse, I have to give serious consideration to the longevity of facilities such as mobile phones and GPS. I build degradation into the system along with some unpredictability. It is almost impossible to work out just how long any of the communications infrastructures we have created to make our world work might last without on-going maintenance.
As for GPS, that will be dependent upon how long the geosynchronous satellites will last in their orbit once they run out of fuel. I believe they have about three years of fuel, maybe more. Considering they have already been in use for varying amounts of time, it is obvious that the accuracy will degrade more or less from day one as each one finally goes offline. I would estimate that useful navigation would last us approximately six months, albeit in variable patches around the world. Watching the Resident Evil series of films I am always amazed at how well the Umbrella Corporation satellites last considering it all takes place over many years. We wish!
Mobile phones. How long will they last? Masts are positioned like a net around the majority of the community. If one goes down the rest can take up some of the slack, albeit not close to the offending tower. The difference between mobile phones and satellites is that mobile phone masts will be vulnerable to damage and destruction. It is likely that most cities will become victims to fire and violence.
Vodafone has an answer. They have built mobile masts and base stations that can be taken into remote regions and erected in mere hours to e-enable communications. They enable local calls initially but can be connected to satellites for wider access. What a great tool for difficult areas.
If these masts/base stations are kept at sites with other emergency stores, then during an apocalypse it might be possible to obtain one: it would enable your group to stay in communication. All you need is a mobile phone each and a base station mast or two. With solar power or generators, they will enable full communications for you and your fellow survivors. They have a range of around seven miles and can support about 100 simultaneous calls. Once you have agreed on the location of your home base, a three metre aerial is a must-have in an apocalypse! Looks like the end of days is no excuse not to stay in touch J
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