Its been a long time since I did any 4 wheeling but I had the same
problem back in the 70s and found that replacing the stock antenna
with a 4 ft fiberglass top loaded CB antenna worked great. Seems like
back then they had a mount just for doing this that replaced the
factory antenna. Dont know if you can still get one or not. My nephew
does this sort of thing and after replacing a couple of CD players he
keeps all his music on an iPOD and plugs it into his broken CD player.

Jimmie

So a CB antenna will work with AM/FM as well? I'm already running a
CB with a 4' antenna - any chance I could use some sort of splitter
and have that one antenna serve both the CB and the AM/FM radio, or
will that screw something up?