very very long range communication

Projects General Guidance
1

Hi,

I'm looking to build a set of identical devices, each showing the distance in kilometres to the other box.

Is it possible at all to communicate this information between the two devices?

Thanks

2

The only way I can think of is to use GPS.

But how will each box know who to talk to, and how will they talk? Maybe Xbee but you said "kilometers" which is normally too far for them although I've heard of 16k with a good aerial.

How many kilometers?

What terrain?

Rob

3

I would use GPS to get the positions and a cell phone shield to communicate between the two devices. There is no unlicensed radio technology that you could use to cover that distance.