"Gary Chenier" wrote in message
om...
I purchased a used motorhome that has a factory installed CB. It's
lousy! Can't transmit or receive more that a half mile. I have tried
to tune the SW on the antenna but no matter if I lengthen or shorten
it the SW stays pegged at the top of the arc. I installed a new, thru
the glass mount antenna, and the same thing happened. I just brought
home a new radio and tried it with both antennas, but no luck.

Any suggestions?

Through glass antennas, on CB, are extreme compromise antennas. Even when
they are working perfectly, they are about as effective as a toothpick.

When you tried both antennas, did you use the same cable? If so, I'd think
that the cable is likely the problem.

If you have a dummy load, attach it at the end of the cable, then read the
SWR from the other end of the cable. If it's not 1-1 then the cable has a
problem. If you don't have a dummy load, then about all you can do is read
resistance from end to end in the center conductor (should be zero) outer
conductor (should also be zero) and from the center to the outer conductor
(should be infinite) but that's not a really good test for RF carrying
cables.

Physically inspect the cable for any "dents" or pinches, if it has any, then
replace it.