In reply to M0SGB:
It’s something I want to have a play with aswell Steve.
You need the following bits: GPS receiver, ham transmitter, APRS encoder. Normally you connect the GPS to the APRS encoder and the encoder to the transmitter. The GPS then sends its position to the encoder, that converts the data to packet tones and the transmitter sends them out. That’s it in a nutshell.
That all becomes a bit messy when you think of all the cables and settings and whatnot that is needed. So… life is easier if you use something like a Kenwood TH-D7E which is a handy and packet TNC in one package. Then you only need to select a suitable GPS receiver and connect it to the D7E. I don’t think Kenwood make the D7E anymore so if you haven’t got one you’d need to find a secondhand one.
Or you can buy “trackers” which consist of an embedded GPS receiver and encoder in a tiny package. All you need to do then is connect that to your handy’s mic and ptt connections. There are many people selling trackers, these people seem to be well respected http://www.byonics.com but a Google search will throw up lots of info. Likewise searching Google for APRS will provide you with more info than you may want.
One thing you need but you can’t carry with you and that’s an APRS network. If there’s nobody with range of you on the hill to receive your APRS transmissions and feed them onto to other APRS users (and eventually the internet) then you’re stuffed.
EDIT: Aha, I see Dick mentions Byonics too. Is the VX-8 on sale in the UK yet?