High CB SWR mystery

[WACJ5]

I put a Cobra CB in my 1956 CJ5 . Did everything according to Firestik and Rightchannelradios installation and troubleshooting guidelines. When tuning the antenna, all channels are way above 3 on the SWR meter.

Checked all system continuity values, continuous when should be, no continuity when that is proper. Changed CBs in case there was a problem with the radio, same high SWR values across all channels. Changed the antenna even though the first one met all checks. Same results.

I would certainly appreciate insight as to what is going on and how to correct the system. The radio is completely useless the way it is.

Thanks.

 

[tarry99]

I put a Cobra CB in my 1956 CJ5 . Did everything according to Firestik and Rightchannelradios installation and troubleshooting guidelines. When tuning the antenna, all channels are way above 3 on the SWR meter.

Checked all system continuity values, continuous when should be, no continuity when that is proper. Changed CBs in case there was a problem with the radio, same high SWR values across all channels. Changed the antenna even though the first one met all checks. Same results.

I would certainly appreciate insight as to what is going on and how to correct the system. The radio is completely useless the way it is.

Thanks.

Where is your antenna mounted and how high & how long is your coax? How close is it to the body?.............a picture would help.
SWR is about reflected energy coming back in your antenna.

 

[CJ jammin]

Check that the connections are clean and tight. And double check that the antenna and coax are matched to the application. Mostly the coax. It's all about impedance matching and you can have a bad match even if the conductors ring out right with an ohmmeter. RF does odd things that low frequency doesn't. And x2 on Tarry99's input.

 

[oldtanker]

OK, I'm about to be a Jeep owner but I have loads of experience with CBs and installation. Couple of questions for you.

Did you get the ant and matching coax?

Did you maybe cut down the coax to make a clean install?

If everything is is connected right and the coax matches your ant you should be able to adjust it from there. If you cut the cable down then your cable no longer matches the ant. Ant location can also affect how SWRs. The best example is the 102" steel whip. Mounted on the bumper or low on the side of a vehicle requires the cable be a certain length. Mount it on the top of the bed rail on a pickup and the cable has to be a bit shorter.

Google it and you can find plenty of info.

Rick

 

[WACJ5]

Coax has not been shortened and measures 16-ish feet. Antenna is a Wilson 2000 Trucker, radio is a Cobra 19 DX IV. Engine, body and frame are all grounded, eventually back to the battery negative post. Here are a few pictures showing the antenna position and mounting.
I appreciate all your comments.

 

[tarry99]

Coax has not been shortened and measures 16-ish feet. Antenna is a Wilson 2000 Trucker, radio is a Cobra 19 DX IV. Engine, body and frame are all grounded, eventually back to the battery negative post. Here are a few pictures showing the antenna position and mounting.
I appreciate all your comments.

Coax Electrical length versus Antenna loading are extremely important to get a low SWR.
Whatever wave length the Wilson 2000 is be it full wave, 1/2 wave or whatever its loading has to be matched to the coax length. I do not like having an antenna as you have with a loading coil that is somewhat hidden. Most are installed so the coil is out in the open.

Reflected energy is what you measure with a high SWR.

A full wave length at 11 meters ( CB Band ) is 36 feet.

Do to the fact that over the internet finding an answer to your question may prove impossible simply because there are to many variables , I would take your rig to a qualified CB radio installer and have that person look over your complete system.

 

[jdarg]

We've done testing w/ several lengths of cable 6' to 18' in 3' increments on the same setup w/ the only difference being the cable and found negligable difference in SWR. What difference was there could be tuned out by readjusting the tip within the resolution of the meter.

Not to insult you but do you know how to properly setup and use the SWR meter?

You also have to have a clean line of sight around the vehicle when adjusting it. If you do it in a garage, etc. or even have another vehicle next to yours, it will read higher than it actually is, sometimes a lot higher.

Also experiment with the ground on your CB. In some cases I've found floating the ground at the radio (the radio then grounds only through the antenna) has a big positive effect on SWR and range.