Any CB experts? SWR's are over 3.0 with new install...

[zimm]

Finished my Cobra install today. But SWR's are over 3! I even tried 2 meters. I went though all the troubleshooting lists on the internet. Everything checks out with the multimeter. No shorts, good ground wire on the mount. I'm left thinking it's just the antenna location.

Guess I'll have to tear it all apart again and try a fender mount up front.

Replaced plastic screw with bolt to strengthen the plastic bumper against flex.

Mounted bracket to stereo adaptor so no holes in the dash!

 

[Hmebuildr]

What channel are you checking your SWR at try 12-14. I have the same set up different mount but same radio and 4 foot firestick. I would also add a spring to your antenna.

Mine is at 1-1.5 depending on the channel

 

[zimm]

Same location? I have a spring to put on there. Tried ch 1, 20, 40. I'll try 12 and also try turning the screw one turn at a time and re-checking.

 

[the_josh]

you said you did ground the mount, do you have a pic? where did you ground it to?

 

[zimm]

you said you did ground the mount, do you have a pic? where did you ground it to?

I grounded it from one of the mounting bolts, used 14 gauge wire, then mounted it to the bolt that holds the little plastic floor piece in on the left side of the interior cargo floor. I ground off the paint so it's bare metal on metal. I know it's grounded because I get continuity from the bracket to the ground in the 7-pin trailer connector using a multi-meter.

 

[fourwd1]

Poor mounting location, and is that bumper piece plastic?

 

[blcktpgsr]

Did you by any chance alter the plastic washer or maybe filed the sleeve on it?
Or perhaps you over-tightened the stud crushing or breaking the sleeve/ lip part of the plastic.

This plastic washer lip or sleeve prevents any metal-metal contact off the antenna stud. I found that the hard way.

Mine initially read close to 5, now it reads 1.3.

 

[JD914]

Subscribing...
Where did you purchase that mount? I'd like to do the exact same antenna setup... once you've got it figured out, of course!:thanks:

 

[JD914]

OK, I figured out which mount you're using, but my next question is can you open the tailgate without it interfering? I'd imagine that even if it does, you could simply push it out of the way when you add the spring, correct?

 

[zimm]

OK, I figured out which mount you're using, but my next question is can you open the tailgate without it interfering? I'd imagine that even if it does, you could simply push it out of the way when you add the spring, correct?

SS-204/204A Adjustable Door Jamb Mount

And yes. I just need to figure out the SWR problem. Haven't tried really tuning it yet. Just tried the screw in the middle, all the way out, and all the way in. Guess I need to try every full turn....

 

[JD914]

Any luck fixing your ground issue? How, exactly, do you go about grounding this? Forgive the questions, but I'm an amateur when it comes to electronics. What sort of wire? Connecting the bracket directly to the truck body/frame?

 

[zimm]

I sorta figured out the SWRs.

Screw up- 3.5
Screw all the way down- 3.0
Screw removed- 1.5
Screw removed AND rubber cap removed- 1.2!

This is with the Heavy duty spring on. Can I run the antenna without the cap on it?

I also ordered a shorter 3' firefly to see how that works.

I don't think it's the mount or location, just the antenna length.

 

[zimm]

Any luck fixing your ground issue? How, exactly, do you go about grounding this? Forgive the questions, but I'm an amateur when it comes to electronics. What sort of wire? Connecting the bracket directly to the truck body/frame?

I grounded the mount with some 14 gauge wire- used a ring terminal to one of the bolts on the mount, ran it up under the taillight, into the truck, and used the bolt that holds down the plastic floor panel inside the cargo area- just inside the door. I used a grinder to get down the bare metal, the put a ring terminal under the panel so the bolt goes through it and bolts it to the floor.

So there's not a grounding problem, its just the antenna tuning.

 

[zimm]

OK, I figured out which mount you're using, but my next question is can you open the tailgate without it interfering? I'd imagine that even if it does, you could simply push it out of the way when you add the spring, correct?

It rubs a little on the edge of the tailgate if you don't push it out of the way. I usually hold it over so it doesn't rub the paint off the tailgate, but for those moments when your hands are full, it'll still open and close without touching the antenna.

 

[JD914]

Great, thanks for all the help. I'm ordering up the same setup (CB is already on its way).
I've thought about doing the Little Will with a quick hookup so I don't have to keep it on the roof full time, but I think having it up there continually getting knocked over by branches on the trail will drive me nuts.

 

[JD914]

Zimm,

I finally got the same exact setup installed, and I'm now having the same issues. I added a heavier duty ground, and I'm able to get channel 1 down to under 1.5, but channel 40 is still over 2. I have the screw completely removed, and if I even put slightly to lengthen the antenna, both channels shoot up over 3.
Anybody have any additional advice?

 

[zimm]

I switched mine out for a 3' antenna and it's at 1.2- a little better than the 4 footer. No screw, but the cap is on there. With the 4' I couldn't run the cap as the SWR would be over 2.

 

[JD914]

Are you at 1.2 on both channels?