Baffled even after research

Place to come if youre having technical issues, including mic wiring

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Stu2985
New to the Scene
New to the Scene
Posts: 1
Joined: Sat Oct 18, 2014 1:23 pm

Sat Oct 18, 2014 1:37 pm

Hi all. I have always held off asking a question on CB unless I have done my research first. However I am baffled now. After years of average reception of my Discovery using mag mounts etc this year i finally drilled hole in the steel roof to sort my CB out once and for all.

I have a Maxxon CM10 that is mounted to my roof using a Thunderpole side mount kit with a swivel knuckle adapter on it that makes it point upright. I am running a thunderpole orbitor.

My SWR was around 1.5 and less than 2 when i ran through the checks on channels 1 and 40. It used to pick up and transmit very well and I could have my squelch turned down low.

After a few months and a few green lane trips and a few bangs on the orbitor I now find as I drive along i get a lot of interference (Similar to having squelch set too low as opposed to engine interference). Sometimes I can cycle through all 40 channels and I still get it. I retested the SWR and its still below 2.

I had a look at where the cable connects to the inner of the roof on the threads of the bolts that come through from the mount and they appear tight and corrosion free. If I use my oribitor back on a mag mount the interference stops but my swr is almost in the red.

Is it possible that something has broken , wet or damaged with the mount ? I cant see anything obvious or should I still be looking at earthing issues with the wires connected to the mount ?

Driving me nuts. Thanks in advance for any help and advice.
bobthetank
Good Buddy
Good Buddy
Posts: 22
Joined: Thu Sep 17, 2015 1:29 pm

Thu Sep 17, 2015 2:04 pm

Sounds like you have lost the earth braid off antenna mount and radio is finding a earth thru the negative power lead to ground antenna.
take pl plug out of radio-check outer of plug to vehicle body with a DVM meter on resistance test,check it reads zero ohm or as close as.
check centre pin of pl plug to vehicle chassis with antenna removed,check no shorts on DVM to ground.
fit antenna back check continuity from pl centre pin to antenna whip,you may have to extend dvm leads to check continuity should read a few ohms.

hope you fix problem

bob
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