 | Home > Technical > Calling my Defender Christine.. |
 
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| bpman Member Since: 21 May 2008 Location: Oslo Posts: 8069  
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why not Carrie ?
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8th Dec 2013 9:28am |
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| kmac Member Since: 07 Oct 2009 Location: Middlesex Posts: 1309  
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After the (old) movie
http://www.imdb.com/title/tt0085333/ Hope my own character doesn't change to reflect the evil nature of my car. |
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8th Dec 2013 9:34am |
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| bpman Member Since: 21 May 2008 Location: Oslo Posts: 8069
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yeah, I was thinking of the film too .. telekinetics, things switching on and off by themselves
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8th Dec 2013 11:03am |
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| kmac Member Since: 07 Oct 2009 Location: Middlesex Posts: 1309
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Still cannot get my SWR below 2
Installed it where the CD/radio antenna is - SWR was 3.0 Ran a cable from antenna to chassis, came down to 2.5 Perhaps need to scrape off some of the Waxoyl on the chassis where the cable connects so I get a better earth Need it to be around 1.5 Any other ideas? |
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8th Dec 2013 5:42pm |
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| bob neville Member Since: 30 Apr 2009 Location: Marbella Posts: 3248  
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Definitely scrape some waxoyl off to get a good earth.
When I first fitted a CB to my 110 I could not get the SWR below 2.5. I was using a Mini Springer. These are supposed to be tuned from the factory but sadly they are not well tuned. What I did was undo the grub screw that holds the mast in the base and removed the mast. Then I got a coat hanger and straightened in up and removed all traces of paint from one end. The diameter of the Springer mast is about the same as a coat hanger. I then cut the hanger to the same length as the mast and fitted it to the base. I then tested the SWR and it was 2.5 still. Now the tedious bit. Take the hanger out of the base and remove a little, I filed off about a mm. refitted and SWR was down to 2.2. Did this two more times (so about 3mm removed) and SWR was down to 1.8. Tested all channels and the highest reading was just over 2 on the worst channel. Last job was to file the same amount off the mast fit and test. I have fitted a couple of Mini Springers now and they have all needed fine tuning to get a low SWR. Bob 2015 Jaguar XE240 R Sport - goes like ....... !! 2013 Defender 90 CSW - sold 2009 Defender 110 Double Cab - sold 2001 TD5 90 CSW - offroad project - sold to a forum member 2011 Porsche Boxster - for the sunny days ! |
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8th Dec 2013 6:24pm |
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| kmac Member Since: 07 Oct 2009 Location: Middlesex Posts: 1309
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Thanks for that bob, didn't realise they were so sensitive to just a few mm.
I have a 1.55m stinger springer orbiter aerial Now to find a coat hanger that's 1.55m long.... Also ground cable is on 2mm sq ( though rated to 25 amps), might get some thicker cable |
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8th Dec 2013 6:45pm |
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| bob neville Member Since: 30 Apr 2009 Location: Marbella Posts: 3248
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I would go for a thicker ground cable as well.
You can shorten the actual mast if you want, just remove a little at a time. The mast can be extended in the base by undoing the grub screw and pulling the mast out a small amount if you remove a bit too much. It might be worth checking if it is fully seated in the base before shortening it. I would guess that the longer mast might be more out of tune than the shorter ones, could be wrong though. Bob 2015 Jaguar XE240 R Sport - goes like ....... !! 2013 Defender 90 CSW - sold 2009 Defender 110 Double Cab - sold 2001 TD5 90 CSW - offroad project - sold to a forum member 2011 Porsche Boxster - for the sunny days ! |
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8th Dec 2013 6:56pm |
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| Lou Sparts Member Since: 15 Apr 2012 Location: Kent Posts: 1501 
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IIRC from my CB days (a very long time ago) if the SWR is higher on channel 40 than channel 1 you need to shorten the aerial and if higher on channel 1 than channel 40 you need to lenghthen it.
Also aluminium does not make as good a ground plane as steel so may well struggle with SWR on a Defender. Mounting the aerial on the wing it may be picking up its own signal being reflected from the upper bodywork and this will also affect the SWR better to mount the aerial up higher on the roof (will also get better distance from there) Happy to be corrected on these points by some of our amatuer radio types on here if i,m talking balderdash. 2005 Td5 90 XS Steve |
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8th Dec 2013 7:32pm |
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| bob neville Member Since: 30 Apr 2009 Location: Marbella Posts: 3248
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Sounds about right to me Lou
Edited to add link. http://www.wikihow.com/Peak-and-Tune-a-CB-Radio Bob 2015 Jaguar XE240 R Sport - goes like ....... !! 2013 Defender 90 CSW - sold 2009 Defender 110 Double Cab - sold 2001 TD5 90 CSW - offroad project - sold to a forum member 2011 Porsche Boxster - for the sunny days ! |
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8th Dec 2013 7:37pm |
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