[TowerTalk] Fw: KT34-XA self resonant

[Michael Tope]

Rod,

These figures are from Mike Stahl's old engineering
notebook (c. 1978 I think). Dunno about the problem
on 15 meters. This maybe do to mixing up of dimensions.
It is my understanding that there are several versions
of physical dimensions for the KT34XA. I believe this
is due to changes in the insulator/capacitor tube design
that occured as a result of UV stability problems in
the original insulator design. The updated insulator/
capacitor tube design required some slight adjustments
in the physical dimensions in order to acheive the same
electrical element lenghts. This can be seen if you
compare an old KT34XA assembly manual with a newer one.
For example, at W6UE, we have two KT34XA manuals. One is
obviously newer than the other as it has "Mirage"
plastered on it, along with a newer address for the
KLM plant. The dimensions in each manual differ
slightly. When I asked Mike Stahl about this he said
that if I had the newer blue cap insulators, that I should
use the most recent set of dimensions as the changes in
cap design affected the dimensions. In either case,
I believe the electrical self resonant frequencies that
he gave me should hold. The 15 meter problem may be
the result of someone using the an older set of dimensions
with the newer physical design (or vice versa).

At any rate, our results at W6UE seem pretty good so far.
VSWR curves are good on all three bands and the antenna
seems to play like a directional antenna. In A/B tests
with a christmas tree of 5 element monobanders on 10/15/20
the KT34XA holds its own, although its tuff to make direct
comparisons as the tribander is a bit too high for this
portion of the sunspot cycle (114' versus 70'/80'/90' for
the monobanders).

Hope this is helpful.

Mike, W4EF................................................


----- Original Message -----
From: "Roger Graves" <rgraves@uvic.ca>
To: <w4ef@pacbell.net>
Sent: Tuesday, August 15, 2000 1:29 PM
Subject: kt34xa


> Mike,
> I just found your msg below. Could you email me the resonance data you
> mentioned? Also, do you know if these figures are for a correct kt34xa, or
for
> the faulty (15 mtr mistuning) kt34xa?
> Thanks & 73,
> Rod VE7VV

----- Original Message -----
From: "Michael Tope" <w4ef@pacbell.net>
To: "Kurszewski Chad-WCK005" <Chad.Kurszewski@motorola.com>
Sent: Wednesday, August 09, 2000 3:02 PM
Subject: Fw: KT34-XA self resonant


>
> Chad - FYI
>
> Mike, W4EF..............
>
> ----- Original Message -----
> From: "Michael Tope" <w4ef@pacbell.net>
> To: "TowerTalk" <towertalk@contesting.com>
> Sent: Tuesday, August 08, 2000 9:40 AM
> Subject: Re: KT34-XA self resonant
>
>
> > Several people replied to me asking for the KT-34XA
> > element self resonant frequency data which K6MYC had
> > sent me several months ago. Here is a copy of the data
> > that I got from Mike.
> >
> >
> > REF 10    27.8
> >     15    20.9
> >     20    13.8
> >
> > RDE  10    28.75
> >      15    20.925
> >      20    14.030
> >
> > FDE  10    29.4
> >      15    21.86
> >      20    15.075
> >
> > D1   10    29.35
> >      15    21.9
> >      20    14.34
> >
> > D3   10    29.15
> >      15    21.38
> >      20    14.6
> >
> >
> > Please bear in mind that this data will only provide
> > a useful basis for comparision if you measure each
> > element by itself and up in the clear away from the
> > ground, guy wires, and other conductive structures
> > which might mutually couple to the element under
> > test (Mike had his elements up 28 feet and used a
> > 1:1 balun).
> >
> > Also I should mention these numbers are based upon
> > the original KT-34XA dimensions. Mike claims to have
> > squeezed another 1dB of forward gain out of the design
> > via computer optimization, and then used this data as
> > the basis for the M-squared KT-36XA  and his KT-34XA
> > rebuild kits. I don't have these new dimensions or
> > element resonant frequencies.
> >
> > Hope this is helpful
> >
> > 73 de Mike, W4EF...........................................
> >
> >
> >
> > ----- Original Message -----
> > From: "Ed Garman" <k9tx@mc.net>
> > To: <w4ef@pacbell.net>
> > Sent: Sunday, August 06, 2000 6:09 PM
> > Subject: KT34-XA self resonant
> >
> >
> > > Mike,
> > >
> > > I read your posting regarding the element self resonant frequencies.
My
> > > XA is on the ground for rebuilding.
> > >
> > > If possible, could you email me the list of element self resonant
> > > frequencies?
> > >
> > > It would be greatly appreciated.
> > >
> > > Thank you,
> > >
> > > Ed
> > > K9TX
> > > Crystal Lake, IL
> > >
> > >
> >
>


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