in this pic you can see the mount
heres another
This is a good option./\
On the roof its self would probably be the best for performance but if you go into garages, trees or anything that hangs low your antenna will take a beating.
Putting it on the fender farther away from the body should work better (performance wise) than a bumper mounted antenna. With a bumper mounted antenna you have allot of metal close to the antenna and that could affect performance.
Get a top loaded antenna and make sure it sticks at least a foot or more above the vehicle for better performance. If it doesn’t go that far above the body it doesn’t mean it won’t work. It just means it may not transmit and receive as good, but will probably be more than adequate for closer communications like on the trial.
The higher then antenna the better it will probably perform, but the more likely it is to take a beating. There are tradeoffs. You may want to suffer on the performance side in order to keep from destroying antennas.
It is better to mount the antenna right to the body as opposed to a trunk, hatch back, door or anything else that attaches to the body. It is very important to get a good ground. Your mount can be a good ground but you should sand the paint off and attach to clean metal. Door, hoods, hatches etc. attached to the body with hinges. These hinges will be painted, so will the body where they attach. That is two layers of paint to get in the way of a good ground.
How you mount your antenna will have the greatest effect on how well you CB works. You can have the best CB in the world and a poorly mounted antenna and it won’t work as good as a cheap CB with a properly mounted antenna.