Devo 10 A7105 problem

I added a A7105 Module to my devo 10. Hubsan Q4 is working fine. TRex 100 most fine - several time the connection break for a short time and heli goes to ground. Anyone an idea what I have to ceck?

Now - i have checked a lot soldering my antenna directly to the A7105 increase the output power (until my coffee was cooking on my desk) my poor TREX 100 several times falling down in his 5 minutes fly.

Today I had an new idea. I deleted the fixed ID bind the TREX new and start again. This time only 15 cm over ground but the little bird was hovering until the battery was empty stable. Then I decrease the output power to 1 mW (coffee was hot enough) take a new battery and start hovering the TREX again. It seems now it works all good.