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Old 11-29-2012, 08:36 PM   #1
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Need CB swr from a 10, down to a 1

I can't get my swr down to a 1. I have a K40 ugly stick, mounted on the spare tire mount, on the tailgate. I'm using an allum. L bracket with new coax. Do I need to run a ground wire from the antenna or bracket? Would a hold down bracket bolt(by the tailgate, on the floor)work for ground? Any ideas? Thanks

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Old 11-29-2012, 11:33 PM   #2
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I'm in the process of installing my cb too. I would question whether the Meter is working correctly... Then make sure everything is ground completely. Make sure the bracket that you screw your antenna into is put together correctly... That's as far as I go.

And don't try to transmit anything until the SWR is down. But you prolly read that already. It would really suck to jack up the cb unit...

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Old 11-29-2012, 11:49 PM   #3
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What type of antenna mount? Can you post a good sharp well lit close up photo of the mount so we can see how it was assembled and mounted? In most cases of a high SWR, it is the mount that is causing it.
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Old 11-30-2012, 06:54 AM   #4
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How long is you coax. i never run under an 18 foot coax. then run the extra around to use un the extra. Dont ever coil up the extra. I have seen people try to run a 6 foot coax and couldnt get the SWR low enough. Went to an 18 foot and problem solved. not say that would fix your issue not sure. Like jerry said the mount can also be the issue. And it would hurt to run a ground if nothing else seems to fix it. I dont have a CB in my jeep yet but will be soon. I need to buy a smaller CB. This is the CB i have from when i drove truck. Magnum S3175 Amateur Radio with 175 Watt Power, 10 Meter, 50 ohm, unbalanced Antenna Impedance, 10.5 - 15 V DC, negative ground Power Requirement, 7.0 amps maximum Current Consumption, 400 - 2800 Hz Frequency Response, Dynamic Microphone, 600 ohm Mic i dont see the need for something this big in my TJ.
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Old 11-30-2012, 08:57 AM   #5
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Dont ever coil up the extra.
Good to know. Mines all coiled up lol
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Old 11-30-2012, 09:38 AM   #6
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Good to know. Mines all coiled up lol
It does what they call an RF choke. look it up it is pretty interesting. just one of the tricks i learned when i was over the road driving truck hanging out at CB chops. Over the road as a truck driver i got pretty into my CB. like i said tho it is to big for my jeep. I have to run like 10 gauge wire to run it. I could still use it just turn the power down on it but the size of the radio is making it hard to find a place to mount it.
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Old 11-30-2012, 10:09 AM   #7
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For the unbalanced type of antennas we use on our Jeeps, coax cable length has no effect on SWR. The correct length to use is tbe length it takes to connect the antenna to the CB or ham radio with a little extra for possible future needs. Really.
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Old 01-01-2013, 05:21 PM   #8
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For the unbalanced type of antennas we use on our Jeeps, coax cable length has no effect on SWR. The correct length to use is tbe length it takes to connect the antenna to the CB or ham radio with a little extra for possible future needs. Really.
What he said is correct.
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Old 01-01-2013, 05:32 PM   #9
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My tailgate had a poor ground, so when I mounted my antenna bracket to my spare tire carrier, I installed a ground wire between the tub and the tailgate (wire is protected with rubber fuel line.). I also made sure I had metal to metal contact on the bracket and double checked it with a multimeter.

That brought my SWR into the safe zone.

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Old 08-31-2013, 02:14 PM   #10
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I bought another plastic washer. I put one on top of the mount, the other on the bottom. The washers extend half way through the mount. Using 2 washers isolates the antenna from the mount. Now, without further adjustments, my swr is bellow 1.5. Good enough for me.
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Old 08-31-2013, 02:20 PM   #11
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You installed another plastic insulation washer on the bottom of the antenna mount? Can you show a picture of that? There should be only one which is on top if your mount is like the one shown below.

With the style of antenna mount like shown below, the bottom part (labeled "SO-239 Coax Connector" below) must not be insulated from the mounting bracket. Indeed, a good bare metal-to-metal connection is required between the top of the "SO-239 Coax Connector" & the underside of the mounting bracket. That is how the coax cable's barrel connector receives its local ground connection.
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Old 08-31-2013, 09:26 PM   #12
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I had 1 plastic washer I got with the mount. I bought a 2nd washer for the mount. With 2washers, the antenna is isolated from the mount. This got my swr down to below 1.5. Good enough for me.
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Old 09-03-2013, 01:15 PM   #13
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OK. I just rechecked the swr with 2 washers and its still around 10. If I take the bottom plastic washer off, what else do I need to do to get this to a 1.5? I'm tired of messing with this. Is there a better mount to use on a tj?
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Old 09-03-2013, 07:14 PM   #14
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The ideal antenna mount is over a flat metal surface. Since we don't have that on Jeeps, except for the hood, it's hard to get it really low.

A couple of steps - first, check your cable with an ohmmeter. You should have no connection between center and shield.

Next, hook up the antenna to the cable with the mounting Jerry showed you. Check the ohms again from the radio side of the cable. You should have a good connection between center and antenna, and between shield and antenna ground. You should have NO connection between the two.

Make sure your ground is good. That's a major issue. Not just on the antenna, but be sure to ground your CB as well. The negative wire doesn't always mean ground.

Check it in an open area away from buildings, overhead wires, etc.

Good luck. Oh, and 2:1 is OK. Don't expect magic.

Here's a link to firestik's instructions on SWR if you don't have it already.
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Old 09-03-2013, 07:25 PM   #15
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YES, Ground your antenna and you'll have it.
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Old 09-04-2013, 09:52 AM   #16
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Check it in an open area away from buildings, overhead wires, etc.
Also you need to be in the Jeep with the doors closed, no friends standing around, especially next to the antanna.
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Old 09-04-2013, 08:05 PM   #17
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The ideal antenna mount is over a flat metal surface. Since we don't have that on Jeeps, except for the hood, it's hard to get it really low.
Not at all. I have installed probably 30+ CB antennas at the back of 30+ Jeeps and never had a problem getting the SWR typically down to the 1.1 to 1.3 range. I did one two weeks ago mounted on the tail gate, not a great spot for good RF grounding, and it was just under 1.1:1.

Insuring the antenna mount (not the antenna) is properly grounded with a large surface area RF ground and that the mount is properly assembled is all I have ever had to do to insure an antenna has a very good low SWR. If it's over 1.5, I find out what is wrong & fix it.

That is with tub mounted, tailgate mounted, and bumper mounted antennas. Personally, I'd never mount an antenna on the hood since I don't want it constantly in my field of view. Especially since a superb low SWR is possible with a rear mounted antenna if you simply properly attend to the basics.

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YES, Ground your antenna and you'll have it.
I think you meant to say to properly ground the antenna mount, not the antenna. Grounding the antenna would of course make it unusable.
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Old 10-14-2013, 05:51 PM   #18
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Does anyone know of someone in the greenfield Indiana area that has installed antenna on tjs? I replaced the aluminum bracket with a metal one. I'm using one nylon washer under the antenna. I still can't get the swr under a 10. The cb antenna is mounted on the spare tire carrier. As far as I know, the coax is good. The antenna is a k40 ugly stick. I also grinded the paint off the carrier, under the antenna bracket.
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Old 10-14-2013, 07:51 PM   #19
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Check your antenna. both my dad and I had Wilson antennas for a few months and one day I couldnt get the SWR down at all. i tried everything. I took my Jeep to my friend who was way big into radios and he couldnt get it down. Turned out the antennas were from a bad batch and something about them wasn't right. We put Firestiks on the Jeeps and we both get under 1.5 on both 1 and 40.
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Old 10-14-2013, 10:03 PM   #20
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I fought terrible CB reception on my 2006 TJ for over a year.
Two things I did that make my Cobra the clearest CB in a trail string:

1) Ran 8 gauge braided ground wire from bolt holding behind-taillight antenna mount directly to hole threaded into frame under the rear quarter

2) Fixed mount. Isolating plastic washer goes between antenna stick (inner coax wire) and mount, NOT between bottom coax knurled collar (outer coax wire).
In essence, I was trying to make my entire Jeep the antenna when I grounded the stick. That don't work.
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