[CQ-Contest] [TowerTalk] Skyhawk, KT36XA, opinions requested

[Leigh S. Jones, KR6X]

This is interesting to hear about.  I rented N6PN's home in Reseda for
several years where I used, on a few occasions, his KT34XA.  It had
no such performance problem.  Believe me, I was looking for that
problem because my friend W0UA reported similar problems with a
KT34XA in Colorado.

>
> As the Cheif Measurer and Report Writer for the tribander tests, I thought
> I should stick my two cents in...
>
> We were also puzzled by the measurements.  KLM, which was in the final
> stages of life support at that time, was mute on the subject.  Because the
> antenna had been shown to work at W7TSQ's QTH and because the antenna did
> work in some segment of all bands measured, we went ahead with the data.
> We also pointed out that it behaved strangely on 15.  All reasonable to
> do.
>
> Then an interesting thing happened...
>
> When I gave our talk - people started coming up to me and saying things
> like, "My KT34XA acts JUST LIKE THAT!"  They had tried everything you can
> think of to fix it and had essentially given up.  The factory had been
> completely unhelpful. There were no answers.  Others said, "Baloney - mine
> is perfect!"  Everyone had, to the best of their knowledge, assembled it
> per specification to the tenth of an inch.  What in the wide world of
> sports was a-goin' on here?
>
> Then another chance conversation with DL2FBU (I think) and others at
> Dayton. Turns out that a batch of these strange XA's had turned up in
> Europe, as well, and the Germans had traced it to improper tubing
> thicknesses in the 15-meter capacitor sections.  Too-thick tubing
> increases the capacitance between the inner and outer sections, lowering
> the tuning point of the elements sufficiently to cause the observed
> behavior.  Trouble was, nobody at the factory would 'fess up to this, even
> after the company went belly up.
>
> To make a long story less long, a very subtle shift in a critical element
> was inadvertently made in a batch of XA's.  Everything can be assembled
> EXACTLY by the book and the results will be as shown in our report - it
> has NOTHING to do with attention to detail.  If you have one of these
> antennas, you will have to replace the improper tubing with material of
> the correct wall thickness to restore order.
>
> I have spoken to Mike Stahl of M2 about it and am writing a short article
> that will, hopefully, alert owners of the mutant XA's to the problem.  He
> is deciding what to do about offering a kit to fix the old XA's, although
> it will likely wind up being cheapest to just offer a 34-to-36 conversion
> kit.
>
> This was exactly the effect desired for creating a publishing a protocol
> and test data.  Along with a discussion of testing and relative behavior,
> anomalous performance could also be identified and discussed.  Perhaps
> with the publication of the article and M2 offering a conversion kit, we
> can help owners of the defective XA's get their money's worth on 15 and be
> happy.
>
> 73, Ward N0AX
>