Phantom 4k disconnects from app

[Aaps]

I used to have a phantom 3 standard and now have a P34k. On the P3S, my phone would relay video from the phantom with little lag upto 600-800ft. Now with the P34k however, even though the controller has perfect connection, the app just says 'disconnected' or 'signal lost' after as little as 350ft. Does anybody have any ideas why this might be occurring? I am using the same app on the same phone (Galaxy s7) and yet the results have been so different.