Having trouble getting out.

Iron..even if cab is on rubber it shouldnt matter..Its a mag mount which means it already on metal..The metal is his gp..
Either its not enuf or its a bad coax or maybe even a bad antenna...Who know maybe coax is pinched off..With a 3 on ch 1 and 40 its still likely gp..

 

I was running a mag mount on my f150 with a with my 955 and never had an issue. as soon as I tried my 2970n4 everything went crazy. High SWR along with a wicked squeal and some slight rf burns. Turns out my frame to to body connection was lacking enough ground. Added some ground straps from body to frame and I was back in business.
3.0 SWR is not good. I would make sure the ground was good enough. Just one of the things that Fine Tune advised me to check before running one of his radios

 

I'd try the setup on a car to see what the SWRs look like.

Also, check the continuity like the picture shows, then I'd try a ground strap from the cab to the frame.

The antenna should be one that is designed for CB use. I've seen really short antennas less than 2 feet long yield high SWRs even when installed correctly.

 

He is on a skidder...Not that i have used one but last ones i saw had tons of metal up top...Not like our plastic 18 wheelers..

 

I always get a buzz in my radios when a ford goes by....Big diff in a 955 and a n4 as well..Uses more power and puts out more power..

 

Saw a vid of a fella with somewhere between 1000-1500 watts useing a mag mount with a sirio..

 

That is exactly what I was running at the time. A Sirio Mag mount and a Sirio fighter. Which is just a Sirio 5000. As soon as I put the 2970N4 inline. My SWR went up to 3.0 and I would burn my lip on the metal screen on my mic from the RF coming back through the radio. I had to add multiple grounds from body to frame. I ground the neg on the battery to the frame and then decided to go with a puck mount and all my problems went away. I am no expert. But, I can only tell people what worked for me.

 

If your getting lip burns off the Mic grill, easy-fix is run a ground strap off the radio to the firewall...You can use the mounting bracket screws or one of the small screws that holds the covers on...no more lip burn.

 

As soon as I ran more ground straps from frame to the body and went with a puck mount. The RF burn and the high SWR straightened right out. Mag mount wasn't doing it.