Cant get my SWR's down?

[Mighty HD]

This is becoming a nightmare.

 

I hope someone can steer me in the right direction. 04 sierra 2500hd shortbed ext cab.

 

I'm testing the SWR in an open area. Radio is a uniden 68xl tweaked. I'm using 18' of rg58? coax, firestik II 4ft antenna mounted directly in the center of the front bed rail just behind the cab on a small spring.

 

I have tried a new mount, new cable, new antenna, grounding the mount directly to the frame with 0 gauge wire, running a ground straight to the battery, to the cb, and to the mount, then to the 0 gauge ground....

 

SWR's are still 2.5, and 3+ on 40.

The radio has a tuneable tip, I have it screwed all the way in and 40 is still higher than 1.

 

What is the deal...can someone P-l-e-a-s-e shoot me some help before I destroy this radio with a bfh...

[Tucson_02Silverado]

Is there any change on the meter, even slight when adjusting the antenna?

Are there changes adjusting at channel 1 then 18-23 then at 40?

Turn the antenna in it's mount at 45 degree intervals, any changes?

 

Not that it would be a permanent position, bumper? can it be adjusted?

 

Do you have aftermarket window tinting that possibly contain too much metal particles (heat rejection)?

 

Radio correctly grounded, maybe add "radio frame" ground