I am designing this TX mod to use Droidplanner with big phones or tablets. I am planning to use for photogrametry with multicopters and planes.
I use mavlink telemetry through gitsly/openLRSng (https://github.com/gitsly/openLRSng)
I think it is a great solution because it is only one antenna for controls and telemetry, very simple and clean solution.
Telemetry stream through openLRSng is slow (19200bps maximum) than I've tried it works perfectly except because droidplanner failed to load the parameter list probably due a timeout, All the rest seems to work perfectly.
I connect my Note with 20cm OTG cable, i have build a custom module cover to fit into a FTDI adapter:
Droidplanner seems well made software, very quick, very intuitive.
My sincere congratulations to droidplanner team
Hope you like!!!