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I just bought a cobra 19 cb with a Wilson 4 ft adjustable antenna with 18 ft of coax. I got a mount of eBay that some guy makes. I hooked up the cb and have tried to tune it for about 2 hours now. I have moved the adjustable tip everywhere. I have taken apart the mount a couple of times to make sure its right. Please help I'm pulling my hair out.

View attachment 91133



View attachment 91134
 

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I don't think that adapter below the coil needs to be there.

Donn
 

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That's not a coil or an adapter. That's a spring and the coupler nut that's part of the antenna mounting stud. I'd check the SWR without the spring, with the antenna threaded directly into the mounting stud. A spring can make your overall length beyond the adjustment range of your adjustable tip antenna.
 

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Have you made sure the center conductor of your coax is not grounded and has good continuity from end to end? Then make sure the shield (body of the coax connectors) has continuity from end to end. Lastly, make sure there is NO continuity between the shield and center conductor. If you have a friend that has a CB, try their antenna on your mount. You can check your antenna for continuity from the stud mount to the tip if the tip is metallic, which it should be if it's adjustable.
 

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Nope that's not it. I just tried that. Swr was at about 10 after I moved that adapter. Thanks any other ideas
You removed the spring and screwed the antenna directly into the mounting stud? There's no adapter to remove unless you were talking about the spring itself.
 

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I've been having this issue myself...still unsolved. Tried 2 antennas, tried with and without spring, 2 radios, 2 coax connections, adjusted antenna as long as possible and as short as possible...ensured my taillight mount had both a good ground to the body and a good rf ground (ground away paint around all bolt holes to ensure a solid connection AND ran a separate ground wire to the body). Meter shows good continuity from center conductor to center conductor and from outer shield to outer shield. No continuity from center conductor to outer shield.

When I try to tune it... meter pegs at around 8 on all channels. I also get serious engine whine in my radio when I'm driving with it on. I'm assuming either I have a bad ground from my battery to my frame or body or a bad ground to my radio. I've tried various grounding locations to hook my radio ground to though and even ran a ground directly to the negative terminal on the battery. Still no luck...I'm hoping replacing my main ground wires may give me some results. Just haven't done it yet.
 

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Going to test the coax but how do u do that.
Get a digital multi-meter (DMM) and set it to measure resistance (Ohms, , continuity, etc.) and place one lead to the center conductor of the coax and the other lead to the threaded collar. There should be no reading between the two. To understand what continuity looks like versus none, just touch the two leads together and you’ll see the difference. Then check from center conductor to center conductor and threaded collar to threaded collar.

You also need to ensure that the doors are all closed when testing and also ensure a good ground for the radio to the Jeep; you cannot rely simply on the ground from the antenna for the radio. Test that the same way you did the antenna (and with it disconnected) but this time there should be a reading.
 

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1. Double check you have the jumper cables on the meter set correctly and then that you are using the switch on the SWR meter on the correct setting.

2. If you double check above and all's good then run a ground wire from the antenna base to a good ground on the Jeep chassis, and try again and see if your readings come down.
 

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There should be an insulator between the bottom adapter and the antenna mount, just like on top. It doesn't appear to have one.

Donn
 

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That would be correct.
 

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You do not insulate the bottom connector. This is your contact for the coax sheath. You do insulate the top, the coax core.

I know it ha been said, but, boy, that's a lot of added length with the whole spring get-up.

If you find someone with a nice MFJ meter that has a variable frequency capability, you can try frequencies above and below the band. If you get a good SWR at 20mhz, you know your antenna is just too long and it's not a cable problem.
 

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Only one insolater came with that mount and the diagram says to put on top if the mount
Ya.......I just noticed you are conecting your coax with a pl259 connector, if you are hard wiring the coax to the antenna then you need an insulator on both top and bottom.

Donn
 

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I now have a ground wire and now the SWR is about 3.5 now what

Adjust your antenna tip and see if you can get the reading down further. Use channel 20 to start.
 

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Try it without the spring in there, it's adding length. The short fibreglass antenna, are not designed for use with the spring. It should be flexable enough without one, even banging around in the bush.
 
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