New set up

100% we have to use the mirrors because with what the modern day trucks are made from and with the stand up sleepers. It ends up being usually the only alternative. I would get a mag mount for that antenna & place it right in the middle of the roof. You need a good ground plane for that antenna to work best. I agree with the other comments too about bypassing that amp and check it. Most of the cb amps are dirty. They are usually class C amps.
good luck, Mike N0KFC

 

He's in a pickup truck. I've tried to convince him not to imitate a semi truck.

 

you are sure right about drilling a hole in the roof. That would be the best bet by far. Although niw days that would be a killer at trade time. Those F250's pull some crazy prices these days.

 

We had one too it had the 7.3 diesel. They love to pull. I still miss that truck, plus I loved the fumes! Congrats on getting that swr down. You should get much better performance with that mounted there.

 

Yep I think you need some thing called a ground. The rack you have the antenna on sounds like it isn't grounded to the truck, and what ever a bandit xl300 is (I assume it is a cheap linear), get rid of it if you don't need it until the other issue is solved.

The mic thing is interesting but it isn't unknown - the reason I think you got a linear.

 

"VSWR" is a proper term for SWR; it stands for "Voltage Standing Wave Ratio". Purists like me and engineers like MsJamie are likely to use the right terms when we need them.

Your ladder rack is not likely to provide enough counterpoise (or "ground plane", as it's usually referred to, however inaccurate that term is), especially when the arrangement of ladders on the rack is changed. Try putting the mount someplace on the roof that doesn't have a ladder sitting right alongside it. And unless you've prohibited by company policy or spousal QRN, find a place that's pretty good with the magnetic mount and then drill a roof in the hole there for a permanent mount. It'll make all the difference in both SWR and antenna efficiency. Speaking of which, keep in mind that a good SWR can come from coax full of water or a dummy load on the end of the coax. Tuning a bad antenna for good SWR (VSWR, as I use it) does not necessarily yield a good radiator. A 1.0:1 VSWR can be obtained without assuring radiation efficiency. In fact, that's part of how I find a problem in an antenna system: I put a dummy load on the antenna end of the coax and see if I've got a good VSWR *and* good RF output at the end of the coax. If I do, and if the system goes plumb to Hades when the antenna is installed, something's wrong with the antenna.
Using the "scientific method" -- changing only one variable at a time -- is the professional (and quickest) way to find out where a problem is.
Hope this helps,
73