Last week I had trouble trying to remove the CB antenna from my 2011 Ultra. I did finally get it off but I destroyed it in the process. I couldn't unscrew it by hand, so I wrapped the base of the antenna with masking tape and used a wrench on it. What initially occurred is that the plastic around the base turned but the metal inside was basically fused (rusted) to the antenna base. Looking back, I should have tried something like PB Baster on it but I never occurred to me the antenna might have been rusted.
Should one use dielectric grease on the antenna base when installing the antenna?

 

It wouldn't hurt if you are going to constantly install/uninstall it. It will repel water and prevent rust on the threads.

 

If I'm not mistaken there is an allen head set screw in the base of the antenna that you need to loosen before you try to unscrew it.

 

Not on my '12.

 

There is no set screw on his model. Those went away a few years ago.

If you use dielectric, keep it near the base of the stud on the tour pak. Remember you can over-do it with dielectric, it is an insulator and can impede conductivity if too much of it is gobbed on. Your case is kind of interesting, I've heard of only a couple of those antenna studs rusting.

Here is what is inside the plastic on that CB antenna:

 

on the stock antennas no, but if you have the HD shortys, then yes there is an allen screw to 1. keep them from coming off and 2. to keep them from getting stolen