I am currently trying to set up a Baofeng UV5R for APRS and I have the BTECH APRS-K1 Pro with the built in TNC. I'm using my phone for the APRSdroid app. I've done all the corrective settings in the app and the radio, but I cannot find the "sweet spot" adjustment to keep the radio from doing a premature TX. But I cannot get it to work. It either premature TX or not at all when I press the Send location button on the app. Any help would be appreciated.