I have had a similar setup for several years. A Force 12 C3 and an XM240.
There is a little more than 10 feet separation. I found that there was some
interaction (not like yours) so I turned the C3 90 degrees and that helped a
lot. I think, if I remember correctly the interaction was on 15 and 40 and
it detuned the antenna about 100 KHz. I can't imagine that yours has an
interaction like that. I suspect that something is wrong with one of those
coils, probably on the driven element.
Bill W5VX
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Steve
Baughn
Sent: Friday, October 09, 2015 2:15 PM
To: Russ Dearmore; towertalk@contesting.com
Subject: Re: [TowerTalk] Cushcraft XM-240 problem
Thanks Russ and Mike,
I don't like to put all my eggs in the MFJ basket but have to say the rig
here (FT1000D) and RF applications wattmeter basically confirmed what the
259b said. I think the next step is to rotate the boom 90 degrees and see if
that makes any difference. After that I may drop the TH-11 since it is
easier to get to and see again if the results change..I am only using 1
feedline and have checked it forwards and backwards. Will report back when I
get this figured out
73,
Steve, WD8NPL
-----Original Message-----
From: Russ Dearmore via TowerTalk
Sent: Friday, October 09, 2015 11:29 AM
To: towertalk@contesting.com
Subject: [TowerTalk] Cushcraft XM-240 problem
Steve, I was having similar problems in which logic was no help and it
turned out that my MFJ antenna analyzer was bad. Since then my bread and
butter analyzer is the iPortable iP60z. I now have 2 analyzers and it has
saved me a lot of time for sure.
Also once when I was really stumped it turned out that I had fried my coax
switching relay. After that I use single coax runs exclusively. Both
problems produced weird resonance dips. These problems shouldn't have been
that hard to figure out but I made it a real circus by trusting bad
equipment. Hopefully you have been able to verify your test equipment and
they are good. Sorry if my reply is too simplistic.... Russ K5ZZR My
Heroes Wear Combat Boots!
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