mobile setup

[burbman]

hello a couple of years a go i drove a truck and i had a wilson fiberglass FGT 4' fiberglass antenna on my drivers side with a heavy duty stud mount and 18' of coax with a good quality cobra radio and when i was sitting still could transmit fine but when i started driving down a bumpy asphalt road or started getting into the dirt roads that i normally got into or started even moving the sq tone would get louder and softer as the antenna swayed back and forth and if one of the operators would try and get me on the ch we use which is 3 i could hear him but barley the sq was almost as loud as he was but when i stopped the truck and called for him he could hear me but i passed the road we were working on and tried to tell him i was back from going somewhere i don't think he could hear me what would have been the problem a bad ground ?

[poboy309]

bad ground would be my guess.

[burbman]

how would i solve that

[rayray1963]

If the antenna is tight in it's mount, I would next check to see if the mirror brackets were tight at all connecting points. I had this problem on my Frieghtliner when I first got it. Check the bracket to see if it's cracked along with the PL259 connectors on coax. Sounds like something is loose and losing ground when truck is moving.
It that doesn't help, then running a short braided ground strap from the antenna mount to the cab maybe enough grounding. If not then add another from the door hinge to the cab and then cab to frame.

[burbman]

ok but the really weird thing was that i was getting really good swr readings 1.4 highest reading