Has anyone thought about installing an YAESU FTM-400DR in their plane for APRS tracking and messaging? Looks like you could get tracking and messaging all in one box Thinking out loud, could you wire one to your Garmin 340 audio panel and use the radio?
I've used Kenwood's TH-D72A when fling in other people's planes. I have the "Granda Special" from HOLA ("Howell Offspring Labor Antennas" a fine USA company )
I tested messaging once or twice while stationary at ZERO AGL, but the workload was too great to even walk-and-message at the same time