CB antenna on FL Cascadia '16?

Hi all! I'm new here, and just had a question. I'm currently in a 2016 Freightliner Cascadia (company owned, just assigned). I originally had two open coil antennas cophased on the Wilson mirror mounts. I had no problems until recently. I couldn't get my SWR below 3 all the sudden, so I switched the antenna mounts, coax, and even tried running a single Wilson 4' fiberglass antenna drivers side. Currently I'm using the built in antenna, and now I'm starting to get large static spikes and I'm watching my rf needle rise almost all the way and then come back down (Cobra 29ltd classic). So I'm not sure if it's an antenna issue, a radio issue, or if the mirror mount isn't truly grounded (as I'm currently looking for a multi-meter to check that). I'm seeing that basically a 7' Firestik is going to be the best bet in a Cascadia. And if my mirror mount isn't truly grounded, where and how would I run grounding straps?

Sorry if something like this has already been answered. So far searches turn up nothing.

 

Thanks for the answers guys! The straps go door hinge to door hinge, or mount to door hinge? I do have the 2 bolt mirror mounts, but I do believe the antenna mounts themselves are non corrosive. It doesn't say it has a finish, but that it's "Stainless steel for a non-corrosive mount." Is that the same thing? If so would I be looking for aluminum? Will definitely pick up a ss opposed to a fs, I forgot they didn't have tuneable tips.

 

The problem was this, happened by a Love's and picked one up that doesn't have the anti corrosion. Put it on and all works good. Door still isn't grounded when open so I'm going to check a CB shop here and see if I can't get straps. Thanks a lot! Would've driven me crazy before I'd figure out it was the mount itself!

 

Definitely going to pick one up. Used to have one, not sure what happened to it. Thank you again!