I would love to say "Get your HAM licence and gear up with some nice SDR, amplifier and antennas " but the reality is that a GSM module from china can be had for less than 5$
The A6 from AI-Thinkers and soon to be available A7 (added GPS) will have all you need to stream information to your server at fairly low power using the phone network. These days data only sim are pretty cheap and "pay as you go"
If this is not what you want or need (GSM is not available everywhere) then look for P2P directional antennas in order to minimize the power needed between you and the thing you are tracking.
Look on eBay for old military radios, sometimes good bang for the buck.
Post updates/more info as you go, I am interested to see what you do with this!
PS: if you are at all interested in SDRs, get an RTL-SDR, super cheap and well documented/supported!