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 indigi and I-gate and another remote tracker in my car.
The home station has recenty cahnged from a Pentium 300MHz PC running UI-View, to a modified router using APRS4R . This enables me to leave the station running 24/7 without killing either the planet or my electricity bill. This is connected to a Tiny-2 TNC with an FT-1500M radio set at 10W output. I am currently using a slim jim antenna on the roof of my house. 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 IARU region 1 has recently adopted the "new paradigm" settings. The new recomended system for the UK is explained by M0CYP which also covers the changes that should be made to UI-VIEW.
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.