Guest MJG Posted May 30, 2007 Share Posted May 30, 2007 Surely these are wired the same as a TV co-ax.......... Centre connected to the pin in the middle and the outer shroud connected to the outer. For some reason leaving the outer disconnected on the plug at the reciever end means we get better reception and a lower SWR reading. :unsure: At the antenna base it is clear the outer and the inner are co-joined......is that correct???? Clearly we are doing something wrong.... but what???????? :angry: Quote Link to comment Share on other sites More sharing options...
LandyManLuke Posted May 30, 2007 Share Posted May 30, 2007 At the antenna base it is clear the outer and the inner are co-joined......is that correct???? NOOOOOOOOOOOOOO!!! that's really bad, you're shorting the antenna to ground, a really really bad thing to do. there should be no continuity between the antenna and shield/ground what-so-ever. Quote Link to comment Share on other sites More sharing options...
BogMonster Posted May 30, 2007 Share Posted May 30, 2007 NOOOOOOOOOOOOOO!!! that's really bad, you're shorting the antenna to ground, a really really bad thing to do.there should be no continuity between the antenna and shield/ground what-so-ever. Maybe there shouldn't be but I have found on a LOT of commercially sold aerials (VHF 2 metre, not CB) that the antennas appear to have a dead short between centre and outer inside the antenna, and on some the outer is connected to the antenna mast and the inner appears to be connected to nothing. They are not defective antennas because I have tried several of some types. I always check now when buying an antenna, to make sure that the inner is connected to the mast, and the outer is not connected to anything apart from the ground, the other antennas seem to work but it doesn't seem right to me either. If anybody can explain it I'd be interested! Quote Link to comment Share on other sites More sharing options...
western Posted May 30, 2007 Share Posted May 30, 2007 These might help pl259 build pl259 build up Quote Link to comment Share on other sites More sharing options...
Guest MJG Posted May 30, 2007 Share Posted May 30, 2007 NOOOOOOOOOOOOOO!!! that's really bad, you're shorting the antenna to ground, a really really bad thing to do.there should be no continuity between the antenna and shield/ground what-so-ever. Exactly what we thought.......how ever..... Please explan why the mounts here.. http://www.thunderpole.co.uk/cb_radio_fixed_body_mounts.htm All seem to have have the centre core of the mast as an integral part of the mount... Quote Link to comment Share on other sites More sharing options...
western Posted May 30, 2007 Share Posted May 30, 2007 The centre core will be seperated [insulated from the vehicle body] inside the mount body, the outer braid will connect to the outer section & inner core should/will only connect to the aerial whip. if the inner core & outer braid are allowed to touch, the rig won't last very long & SWR will be incorrect & again eventually damage the rig. just found this too http://www.thunderpole.co.uk/forum/viewtopic.php?t=748 I should have looked there first it should get you sorted & on the air Quote Link to comment Share on other sites More sharing options...
Nigel H Posted May 30, 2007 Share Posted May 30, 2007 As I understood it (back in the 70's - yeah so what?) - there shouldn't be a complete circuit, hence the often nylon washers on the mounts to stop any earthing. tired - best I can do. N Quote Link to comment Share on other sites More sharing options...
LandyManLuke Posted May 30, 2007 Share Posted May 30, 2007 Exactly what we thought.......how ever.....Please explan why the mounts here.. http://www.thunderpole.co.uk/cb_radio_fixed_body_mounts.htm All seem to have have the centre core of the mast as an integral part of the mount... If you study them, you'll find they're not electrically connected at all..... Quote Link to comment Share on other sites More sharing options...
Nigel H Posted May 30, 2007 Share Posted May 30, 2007 I should have looked there first it should get you sorted & on the air Yeah! that's what I meant Thunderpole are well worth a look - lots of info on SWRing etc. ps. CB's aint like radiocassettes/CD players - it's much easier to blow a CB - without knowing why - there's the logic Quote Link to comment Share on other sites More sharing options...
Guest MJG Posted May 31, 2007 Share Posted May 31, 2007 Cheers everybody - need to go back to the drawing board...and look at the wiring again... Quote Link to comment Share on other sites More sharing options...
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