Removing Police Antenna

I have a 92' caprice classic with the police anttena base still attached to the trunk. Wondering on how to remove them. Tried wrench, but didn't work. Any suggestions would be appreciated.

Just curious, why do you want to remove them? The one on my trunk was converted to a CB antena by my dad and the one on my roof was gone when he bought it.

The antenna mounts do have a tendency to rust together, making them impossible to remove. I suspect it is a NMO mount, that has a brass ring around a chrome base. You can try using the wrench on the top brass ring, and clamp a vise-grip on the inside mount. If that doesn't work, you will have to rock, the mount from the outside with a pair of vice-grips untill the fender gives, and it will pop out. You can plug the hole with a 3/4 in ruibber cap. Have had to remove many a antenna like that on numerous Police cars over the years. Good luck