Tuning a cb

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jonny mac

Active Member
Posts
239
Location
north wales
Right so my cb came t'other day have now fitted it with a mag mount on the roof of my disco. I bought an swr meter while I was at it but can't figure out how to tune it in. anyone familiar with these swr testers?
 
Google it cb set up and tells you how to do it step by step as to get best signal you may have to trim the aerial slightly it will also tell you if it is earthed properly etc . Don't use the cb until set up as you can damage the internals of cb . Good luck
 
Just googled it and have gone and had a play. So my swr reading stands at slightly over 3. I trimmed 1/4" off and no difference trimmed a further 1/2" off and if anything it's gone slightly higher. It's on a mag mount so cannae do anything about grounding it further, anyone got some suggestions?
 
Not sure, in the guide I read it just said to check on a mid channel like channel 20 if there's 40 overall. What difference would it make on different channels?
 
20 should be mid point, your electrically tuning Ariel and if it reflects too much rf back it will blow power transistor in set.

the meter should have two settings, briefly key up on ref and set full scale mark unless indicated otherwise in instructions.

flick switch other way and it should be under 1.5 on all channels
 
Ariel is mounted on the roof near the rear centre with a 7" mag mount, I have no roof rack, roof bars, sun roofs or anything like that
 
Ariel is mounted on the roof near the rear centre with a 7" mag mount, I have no roof rack, roof bars, sun roofs or anything like that

Should be ok then....Are you parked next to buildings when testing the swr? Is there adjustment up in the aerial mount? Mine you can adjust longer by not pushing fully into the mount
 
I'm parked on my drive where there are standard two storey houses yes, there is a little bit of adjustment in the aerial but only about an inch or so
 
Couldnt get anything on the roof below 3 then i managed to get it to 1.3 on the bumper which is brilliant apart from the fact that i cant open my rear door while the mag mount is there :( then it took me nearly a week to figure out that the cb was programmed to spanish channels instead of uk ones lol
 
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