Kenwood TH-72D TNC Hint

Well I am doing a comparison between the software TNCs , Direwolf, UZ7HO sound modem, AGWPE and have introduced the Hardware TNC that is built into my Kenwood TH-72D handheld unit.     It was fairly easy to move from doing APRS to being a KISS TNC.   Just press the TNC button on the front panel until you see the message move from APRS12 to PACKET12 and make sure the USB port is on and you are set.  

Weird problem is that it would work intermittently.   Worked pretty well and would drop loose a packet or two and work again.    I wound up looking at various setting and then turned off the GPS and everything started working perfectly.     I am guessing the GPS was adding some data to serial stream and corrupting some of the AX.25 packets.  

So the hint.    Turn off the GPS if using the unit as a generic TNC.