I just installed a cobra 29 ltd in a motorhome. the antenna was already installed by a previous owner. I checked the coax for grounding and it was clear. when I connected the radio it showed swr almost off the scale on the radios meter. not knowing how much of the old antenna had been scraped of the end I replacer it with a Wilson flexible unit and got the same reading. I also connected the small antenna wire to ground as instructed and this didn't help.the coax is run inside the frame so I don't know how long it is. where do I go from here. any suggestions?
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High swr reading
- Thread starter sidewheeler
- Start date
Is this a fiberglass motorhome?
My guess is that if he doesn't have an external SWR meter, he doesn't have a dummy load, either.
If it's a fiberglass motorhome, you have a groundplane issue, which means that you're going to have to find some way to ground the antenna mount.
My guess is that if he doesn't have an external SWR meter, he doesn't have a dummy load, either.
If it's a fiberglass motorhome, you have a groundplane issue, which means that you're going to have to find some way to ground the antenna mount.
You may still have a problem with the feedline or connectors even if they do not present a short on the meter. Something could be loose on the antenna's base, a connector may be bad or loose, water might be in the coax or any number of other things. Since you're having the same problem with two antennas, feedline and/or connectors can be the problem.
If this were my problem, I would basically start looking at the coax and connectors and that would mean I would go through the paths the coax is taking. Actually, i'd be replacing the coax and using new connectors, even though its going to mean some work and take some time, since you've got some long lengths to mess with and you only want to do this right the first time.
And the issue already stated, do you have an aluminum or fiberglass?? You may have ground plane issues to deal with.
Good luck with it!
If this were my problem, I would basically start looking at the coax and connectors and that would mean I would go through the paths the coax is taking. Actually, i'd be replacing the coax and using new connectors, even though its going to mean some work and take some time, since you've got some long lengths to mess with and you only want to do this right the first time.
And the issue already stated, do you have an aluminum or fiberglass?? You may have ground plane issues to deal with.
Good luck with it!
sidewheeler said:
Well i would say just go ahead and replace the coax,and add new stud or so239 connector the coax may have been pinched or broken and being it runs all way down the frame who knows it may have rubbed thru the shield,you did not install the feedline it will give you peace of mind,,once all your coax and connectors are replaced you can recheck,and if you still have issues then you can go from there with antenna adjustments,,more than likely you have a bad run of coax and or an intermitten short..But i may be wrong thats what i would do anyway you can get coax cheap and connectors also atleast it will all be new...73sss Coily
Thanks for all of the tips. The motorhome is in fact fiberglass with a rubber roof. I know that the ground plane is an issue. the antenna mount has a seperate ground wire that is attached and the ground is good. I think my best first step is to run a new length of coax just to see if that corrects the problem. If it does then I can hopefully connect the old to the new coax and fish it thru the frame. I will post the results.
I just returned from where we keep the motorhome stored and I was able to resolve the high swr reading.
The new antenna I installed, screwed down into a base mount. When I attempted to tighten the connection onto the mount it was a little loose. I could not tighten the connector or loosen it so I had to cut it off with a hacksaw. I installed a new end on the coax and a new antenna connection on the base.
Now all is well. Thanks for the suggestions
Larry
The new antenna I installed, screwed down into a base mount. When I attempted to tighten the connection onto the mount it was a little loose. I could not tighten the connector or loosen it so I had to cut it off with a hacksaw. I installed a new end on the coax and a new antenna connection on the base.
Now all is well. Thanks for the suggestions
Larry