TM-D710 Internal GPS (de NF3H)

I’ve got a Kenwood TM-D710A ham radio transceiver. This handy device is a portable 50W dual-band (2m and 70cm) radio, with a built-in packet radio TNC and some native APRS features. What it does not have (unlike the new TM-D710GA model) is a built-in GPS receiver.

This is a problem that can be fixed with a surprisingly small parts budget, provided you’re up for some fine-pitch soldering. Details after the break.