FPV RC Plane Lidl foamie - My Quest Goes on - Have I finally discovered the problem?

Bonzodog

Lidl Master
A while back I built a lightweight Lidl foamie conversion, my no.14, (now converted to my first Lidl pusher,) with the intention of using it as a slow fly FPV plane. I've flown my biggest drone FPV, but that has GPS and RTH, I wanted a slow plane for 1st attempts at aircraft FPV but haven't got the budget for £300 - £400 for Walksnail digital and nav computers, so it's simple analogue VTX. Problem I've had is very poor range and interference, finally last week while making another test I had a brainwave revelation as to what the issue might be! Gales here so no chance to try it yet, but what's opinion here folks? Have I cracked it?