When I put my PAU Edge 540 together, I deciced to run it with 6.0 V Nimh battery with a regulator. Like you I couldn't get 20 paces away. I did as you did changed everything. Finally I bipassed the regulator, and lo and behold no glitch, out to about 60 paces so in desperation, I took the antenne out of the nice little tube installed in the fuselage, ran it straight out the bottom and taped it underneath, now it range checks out to 300'.

Futaba 9C, 149 PCM
Brison 3.2

Good luck, glitches are a btich!

Dale