You need a 3' steel whip antenna mounted as high up as possible. Use the "grounded" type, NOT the "no ground plane" type, and ground it to the subframe with no less than 10 ga wire. Use 9' of RG58U cable....no more, no less! DO NOT coil the antenna cable!! Wrap any excess into a figure "8", then tape the around ends as tight as possible.
The antenna you choose should be able to adjust the SWR setting. I currently run a 2' antenna, but switched it out to a 3' just to see if it was any better. Audio increased almost double, but me being the hard head that I am put the 2 footer back for asthetic reasons only. I didn't want my FJR looking like some fishing troller.
Most importantly was the fact that I use it 99% listen and 1% talk. No difference in Rx between the two different sizes. It only seemed to affect output.
Hope this helps.
I'm currently working part time for a CB shop. I learned more about antenna tuning in the last three months than I did in the last 48 years.
rule of thumb......grounded antennas work best with 12' of cable, absolutely but no less than 9'. You increase the length by 3' intervals if you have to make it longer.
Non grounded or "no ground plane" antennas work most efficiently with a 17' cable. No more, no less. That is, of course, when they work at all. Very tough to tune a non grounded antenna. You can get a false reading just by standing near it. (withing 10 feet) Also, never tune a non grounded antenna between two buildings, like houses or such.
NEVER roll the excess cable into a coil.
Folow these rules and you'll get it right.
