I need help. I am super frustrated.

I have an electrajet. I had been flying it with a Hitec Supreme 8 receiver. I moved that to my sailplane because I now need 4 channels there. I replaced it with a Hobbico 3 chanel AM radio/receiver that came out of my sailplane where it has worked flawlessly. The radio is a private branded Hitec Focus III

I seem to be getting some chatter on the elevons when I do my radio check, but only if the battery is actually in the plane. If it is sitting on the wing, everything is fine. It seems the battery being in the plane is either creating interference, or is acting as an antenna amplifying some kind of interference.

The plane came with a delta mixer. I thought that was what was causing the problem so I removed it and enbabled mixing in the radio. I thought I had it licked. But it is back.

I need some ideas on how to clean this up OTHER than going back to the FM radio. There is no reason why this set-up should not work and I want to figure it out.

If you look at the photos, you see the yellow speed control in the back, opposite the on/off switch. The wire from the ESC runs down the plane's left side, inside the compartment to the receiver.

From the receiver, two lines run toward the rear and exit either side about half way down going out to the servos in the wings for the elevons.

The receiver antenna normally runs down the plane's right side inside the compartment and exits through the fuse then goes out the wing via a channel. You will see the antenna on the red photo (bottom of the plane). However when you look at the receiver, I have rerun the antenna out the right front of the plane and taped it to the outside of the plane to get it away from the interior of the plane.

The wires are up in the air at this time as I tried twisting them to see if that would help. It didn't.

Any ideas why I am having this problem? Any ideas how I can fix it? I am stumped!