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Re: [TowerTalk] TowerTalk Digest, Vol 234, Issue 1

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Subject: Re: [TowerTalk] TowerTalk Digest, Vol 234, Issue 1
From: hp via TowerTalk <>
Reply-to: hp <>
Date: Fri, 3 Jun 2022 15:16:00 -0400 (EDT)
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I do not have a 36XA but have a KT34 rebuilt to latest M2 specs and mechanics. 
It had never been quite right on 15 so when I rebuilt I spent a LOT of time on 
what was going on on 15.SWR was always taking off below 21025 and F/B was lousy 
in CW portion. Long story short - problem was the 15 meter cap tubes were 
oversize ID and the 3/8 tubing was undersize by a few mils on each such that 
could not get the capacitance you needed . So after I resolved that - I could 
good swr and F/B over the band . Look up N6MW on the internet he has published 
a lot o 
of what both he and I and others did on KT34 15 meter problems. 

Now to interaction. 
I was doing the work on a tripod on roof peak about 30 feet under a 40M1L 
rotatable dipole. 
I would get everything just fine (running F/B with a friend about 2miles north 
of me. ) 
Then I would finalize everything and recheck next night and it had gone to 
hell. I was using 
the 40M1L at night and was not attention to where it was left.What was 
happening is that 
the F/B and low end SWR were massively affected by the coupling to the 40M1L 
dipole some 30 feet higher . 
I could move F/B 100khz -150khz by changing orientation of the two antennas. (I 
suspect that one might 
be able to "open" the dipole and reduce the coupling but with the dipole in 
line with the KT34 boom 
it was not an issue ) 

Once I nulled the remote 15M sig on the dipole (end on to the signal) then 
adjusted the KT34 15M traps - everything 
was solid and would stay just fine. My signal source buddy and my Grandson 
armstrong rotator who both thought I was 
crazy as hell were relieved. 

See Bill N6MW comments on KT34 he and I were working on same issues at the time 
and has other data 

Hank K7HP 

Message: 1 
Date: Thu, 2 Jun 2022 14:14:59 -0600 
From: Steve London <> 
Subject: [TowerTalk] Why does KT34XA/KT36XA stink on 15 ? 
Content-Type: text/plain; charset="UTF-8" 

I know I'm not the first one to observe this... 

I have a KT36XA on one tower, and reference monobanders for 10, 15 and 20 
on other towers. On 10 and 20, the XA always performs within a few dB of 
the monobanders (sometimes, even better than the monobanders). On 15, the 
XA is always down about 6 dB from the monobander. This is consistent 
regardless of distance, direction, skip length, etc. Even the "band noise" 
is down by this amount. The SWR on all 3 bands is reasonable. Long ago, I 
also measured the resonant frequency of each element. See . There is a 40 meter beam about 30 
feet above it, but the 15 meter SWR does not change when either the XA or 
40 is rotated, so I don't think there is significant interaction. 

What did KLM/M2 do wrong on 15 ? 

Before you tell me your KT36XA works great on 15, what are you comparing it 
with ? 

Steve, N2IC 


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