CB SWR level is extremely high

Ok, apologies for hijacking this thread, but my problem is the subject of this thread, so here goes:

I have a Uniden 520XL that is wired directly to the battery. From the CB, I have this coax (18') going to a firestik connector on a red hound mount, on which I've put a 2' firestik antenna. Some pics are below, and showing that I've scraped away the powder coating from where the coax meets the mount. That's also where I've attached the grounding strap. I ran the strap to underneath the soft top clip on the back of the tub, and I scraped the paint away under there too. Stuck a washer under the black clip and tightened down with a bolt and nut to ensure a snug fit against the metal.

I have the same Astatic SWR meter that Chris linked earlier in this thread, and I'm getting SWR levels over 3. This is after playing around with antenna lengths, testing in an open area (large empty parking lot), etc.

Some pics are below. Any ideas? Many thanks.

IMG_5443.JPGIMG_5444.JPGIMG_5445.JPGIMG_5446.JPG
 
Not sure if I see this right but you may want to use that 4th hole on the mount. It requires you to drill through the tub. Mine was very unstable without it.
 
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Not sure if I see this right but you may want to use that 4th hole on the mount. It requires you to drill through the tub. Mine was very unstable without it.

Thanks. Mine is stable, so I’d rather not drill unless necessary.
 
It could be a couple of things. The antenna should not be contacting the metal base hence why there is the plastic washer. If the grounding cable is touching the center section or connecting it somehow you just grounded the antenna. It could also just be creating a path for interference. My antenna is a Wilson that comes with an extra grounding wire. As soon as I removed my the swr was perfect.
 
Thanks. Removed grounding strap and left tip off. Now it was a little worse. Hard to say how much because there are no markings past “3” on my meter.

I know the mount is not grounded without the strap, since it is powder coated.
 
Thanks. Removed grounding strap and left tip off. Now it was a little worse. Hard to say how much because there are no markings past “3” on my meter.

I know the mount is not grounded without the strap, since it is powder coated.
Ok this tells me the antenna needs to move up. Try to put the tip on and start adjusting it up little by little. If you start seeing an improvement but run out of adjustment you will need to add maybe a spring or something to raise the antenna up. Keep the strap off for now
 
Ok this tells me the antenna needs to move up. Try to put the tip on and start adjusting it up little by little. If you start seeing an improvement but run out of adjustment you will need to add maybe a spring or something to raise the antenna up. Keep the strap off for now
Thanks. Will try and write back when I have.
 
Ok this tells me the antenna needs to move up. Try to put the tip on and start adjusting it up little by little. If you start seeing an improvement but run out of adjustment you will need to add maybe a spring or something to raise the antenna up. Keep the strap off for now
OK, with ground strap off, I started with the antenna tuned to the shortest length, and raised it a few turns each time. It improves steadily with Height, and at its max possible height I get 1.8 on channel 1, 1.6 on channel 20, and 2.5 on channel 40.

But this is in my driveway. Will repeat from empty parking lot tomorrow.
 
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OK, with ground strap off, I started with the antenna tuned to the shortest length, and raised it a few turns each time. It improves steadily with Height, and at its max possible height I get 1.8 on channel 1, 1.6 on channel 20, and 2.5 on channel 40.

But this is in my driveway. Will repeat from empty parking lot tomorrow.
If you want to chase perfection find a way to add in extra height. Most use a spring. You would probably be able to run without the tip/screwed in all the way with a spring.
 
If you want to chase perfection find a way to add in extra height. Most use a spring. You would probably be able to run without the tip/screwed in all the way with a spring.

If anything those numbers suggest the antenna is a little too long because it appears that resonance is probably between channels 1 and 20. With such a short antenna I doubt you can get any better than 2.0:1 across the band.
 
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If anything those numbers suggest the antenna is a little too long because it appears that resonance is probably between channels 1 and 20. With such a short antenna I doubt you can get any better than 2.0:1 across the band.
Yep you are right. Good catch. All I saw was 1.8 and 1.6 haha.
 
If you want to chase perfection find a way to add in extra height. Most use a spring. You would probably be able to run without the tip/screwed in all the way with a spring.
Ok thanks. Will write again after I test in an open space tomorrow.
 
If anything those numbers suggest the antenna is a little too long because it appears that resonance is probably between channels 1 and 20. With such a short antenna I doubt you can get any better than 2.0:1 across the band.
Yep, was thinking the same thing, and will try a little lower in open space tomorrow.
 
But if this works when I test tomorrow, I’m going to be confused as to why it works better ungrounded than grounded. I have not used the third mounting hole as a ground, and have not removed any paint where the mount attaches to the tub.