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JK CB & HAM Radios Bulletin board forum regarding all topics concerning CB and HAM radios, the installation of them in your Jeep JK Wrangler. This would include antenna mounts, wiring, tuning and usage.

CB Tuning Question (Doors & Top)?

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Old Apr 11, 2008 | 10:19 AM
  #1  
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Default CB Tuning Question (Doors & Top)?

I have been searching for an hour, and I can't seem to find the answer?

Is it better to tune your antenna when the doors and top are on or off? Or does it matter? Thanks!
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Old Apr 11, 2008 | 01:31 PM
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I dont know if it matters or not. Soft top would not.
Why don't you tune it with the doors on and then with the doors off, and let inquiring minds know if there is a difference?
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Old Apr 11, 2008 | 05:34 PM
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Cool. Thanks guys. Good idea, I will give both set-ups a shot and let you know the difference in SWR tomorrow.
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Old Apr 11, 2008 | 06:14 PM
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I don't think you will find a whole lot of difference in SWR either way maybe some but once you match the antenna to the radio (tune it) the performance should be similar in both configurations. I think you would see more differences if you where moving/removing things like metal body panels right around the area of the antenna.

I think if it was me I would tune with your Jeep "fully dressed" this way you tune it for strength against any possible inhibitors...with the doors and top off it would only be easier for the signal to spread anyway.
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Old Apr 12, 2008 | 06:05 AM
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Originally Posted by toad
I don't think it matters, as long as the "human factor" is relatively away enough from the antenna when tuning it. Just my experience.
The body of the jeep serves as your ground plane. Plastic roof makes no difference. Metal doors may make a slight but perhaps not much of a difference.
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Old Apr 12, 2008 | 03:31 PM
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Exclamation I can't tune and hopefully someone can help me.

I have read hundreds of posts on here and information on other sites about how to tune the antenna, but I haven't heard of anyone with the Cobra 75 and a Firestick 4' having to cut the antenna to tune right.

Here are some pictures of my set-up:







Will grounding to the battery work the best? the 75 box is under the glove compartment.

My SWR ratings are 1.8 on Channel 1; and 2.8 on Channel 40. I have taken the QD off and taken out the tuning rod, and that is the best I can get.

Please let me know what I am doing wrong. Supposed to go on the trails tomorrow and would like it working by then. Appreciate it!

Last edited by Rubi-WAC; Apr 12, 2008 at 03:34 PM. Reason: Sorry for the bad photos. Phone is all I have.
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Old Apr 14, 2008 | 08:45 AM
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I have seen the post about the mount. Does anyone see in my pictures why I am getting such a high SWR? Thanks.
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Old Apr 14, 2008 | 09:06 AM
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Well what is the reading on channel 19 or 20? If under 2.0 then there is an adjustment on the Antenna that can be changed to accomodate. There should be a platic cover or rubber that needs to be reseated on the top of the antenna after each adjustment. I do not recall the direction to turn when 40 is reading high and 1 is reading low. Turn 1 full turn and you should see the cause and effect.

If this doesn't work do you have a CB shop nearby? I don't have any here locally so I cannot get them to tune. It's rather cheap in the under $20 range if tuning is all that is needed.
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Old Apr 14, 2008 | 03:50 PM
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If your going to see if grounding helps...ground to the frame, NOT the battery.
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Old Apr 14, 2008 | 04:33 PM
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Default Not sure why this is so hard for me

Well I would like to think I am smarter than this, but I just cannot get anything below 1.8. I can get 40 and 1 on the same level (~2.7) with 20 being lower (~2.3) and that is the lowest possible.

Tried with doors off/on, top off/on, in neighborhood, in huge open land, QD off/on, grounding to battery/frame. Even cut the antenna by 1/8ths of an inch until my SWR got worse by .2.

As much as I like to do everything myself, I am about to take it to a CB shop. Thanks for all the ideas though guys, it made me have hope to go try it again haha. If anyone has any pointers on what still might be my problem, let me know. Appreciate it!
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