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GPS for Tacktick MN100 dual diplay - raymarine
we have bought a second hand sail boat and has the following instruments on board;
I think that the $26 (!) Marine GPS you found will work with your T122, and will hopefully include a wiring diagram or color coding so it easily installs. But you might also consider the well proven and supported Garmin Gps 19x Hvs Nmea 0183:
I can't think of a low cost 12v NMEA 0183 heading sensor, but maybe someone else will pipe up.
And I did find the Tacktick T122 to be quite able when I tried one years ago:
I had a full Tacktick system on my sailboat Jammy 6+ years ago (or longer) and it was a wonderful system with the exception of the masthead wind instrument. I went through several of those, mostly due to battery or solar issues and not connecting to the network down below. The last one I had lasted much longer, and I heard they had resolved most of the issues with that particular unit.