When you used the jumper cables for grounding was there a totally metalic surface without paint??

Another issue is that i think super long jumper cables are affecting the issue..

I was always told to keep my grounding lengths as short as possible..
Example..

Headache rack to something metalic like bed rail....Bed rail to trk bed and bed to chassie..

Swr is not end to be all either..@a q.6 swr your only looseing less than 10% if memory is correct....Sounds to me its not gettin out issue its a rec issue and some good grounding in short lengths will do wonders...

I faught same issues on a volvo 18 wheeler..With my mfj 259b ant tuner i discovered that ant stud mounts made a diff in recieve to...I went from the el cheapo chrome covered basic stud mount to a beefy chrome stud mount to the alluminum colored wilson beefy lookin stud mount..