I have a Phantom 3 Advanced. When I first bought it, I used a samsung tab 2.
The AirData always showed the purple track and poor signal.
Samsung Tab 2 was really struggling to run DJI Go App (even after stopping unnecessary tasks etc).
Got the CrystalSky ordered as soon as it was announced.
AirData now shows excellent / good signal strength (no other changes made).
Samsung Tab 2 was misreporting the logged data.