Install a wifi scanner app, and (with the drone on the ground but connected) hold your phone as you do to fly, and as you do to text.
I noticed a massive drop in signal strength when holding my phone in "fly mode", mainly due to my wedding ring being directly over the wifi antenna.
Im using a phone tripod as a pistol grip to hold the phone. Still not getting more than 30m but on the flipside, at that distance, i can barely see the drone