I'm not saying this is the reason for all these complaints I've seen.
It's just my experiences.

I've been flying my P3S for over 3 weeks now. It's my first drone.
I have tried 3 different tablets and 1 cell phone with it.
Here are my experiences.

Cheap cell phone: Has picture distortion (seperation) every minute or so. But does not lock up.
Totally usable.

Cheap Tablet 1: Won't display picture for more than 2 seconds. Then says 'No Signal'.
Can't use at all.

Cheap tablet 2: Has same picture distortion every 10-15 seconds. Seems to work (for a while).
After 6-8 minutes will start 'no signal' and pic will freeze. Then will clear up.
Shortly there after will lock up and say 'Disconnected' even when I know I'm back in range.
Have to manually RTH on controller.
Must close Go app and restart then it will reconnect. All while bird is returning home.
Somewhat useable. Still testing.

Expensive tablet : Works better than the cheap cell phone. No complaints.
Totally useable.

So if you are seeing no signal on your display consider your display device.
All the while my displays were complaining no signal and disconnecting I still had full manual control.
I may have one tablet that will never work due to display and speed limitations.
The other I may be able tweek into useability.

Aloha roy,

     Yes, you are on to something.  That is how you do it.  But, be careful enough to not crash your Phantom as you figure things out.  It also helps to read the manual a few times and watch all the videos you can find about the P3S and DJI GO.

     But, most of all have fun while you are doing it!

Aloha and Drone On!