APRS
I have recently been playing with APRS, the Automatic Position Reporting System. that runs via packet radio.
Rather than bore you with the details, take a look at wikipedia which explains all. If you are in the UK, M0CYP has a great site with lots of information on settings and how to use UI-VIEW, the most popular APRS software.
I have two stations. One at home that runs as a fill in RELAY digi and I-gate and another remote tracker in my car.
The home station is a Pentium 300MHz PC running UI-View, a Tiny-2 TNC with an FT-1500M radio set at 10W output. I am currently using a Diamond X-500 antenna. In the car I also have a FT-1500M, with a "puck" GPS and a fabulous opentraker+. The antenna is only a 1/4 wave, but that seems to do just fine locally.
If you are active on APRS in the UK, please note that we have a different set of unproto addresses to the US. If you are a mobile use RELAY,TRACEn-n. IF you are a home station use TRACEn-n. If you are active on RF from home, please enable your software to act as a relay digi (not TRACEn-n digi) so as to fillin gaps in coverage.
The aprs.fi does a great job of real time mapping, so take a look for the car or my house using the embedded website image below.