Thanks, Dave! I had forgotten all about the great book you wrote 30+ years
ago. Also, my wife and I are watching a series on TV that we watched 10
years ago and it's almost like we had never watched it.😀
So in the chart it shows the equivalent diameter as 2.14" and the length as
2.925". I am assuming from what I read that the half length of the clam
shell clamp that extends out from the edge of the boom is 2-5/8" with an
overall length of 7.25" (5.25" + 2") and that the length of 2.925 is
derived by adding .3" for half the electrical length of the boom diameter?
Hope that makes sense and is correct?
Thank you so much for reminding me of the book. A lot of it is way over my
head but it's full of practical information as well.
73...Stan, K5GO/ZF9CW
On Wed, Nov 5, 2025 at 12:52 AM Leeson <leeson@earthlink.net> wrote:
> Modeling of the HyGain element clamp is derived in Chapter 9 of my 1992
> book, "Physical Design of Yagi Antennas,"
>
> https://www.dropbox.com/s/hmhkeofz0igrg1e/Physical%20Design%20Of%20Yagi%20Antennas%20D%20B%20Leeson%20V2.pdf?dl=0
>
> From page 9.3, the equivalent diameter of the HG204BA clamp is 2.14
> inches. This clamp model is used in K6STI's YO and other Yagi software.
>
> Dave, W6NL/HC8L
>
> On 11/4/25 5:43 PM, john@kk9a.com wrote:
> > Maybe easy for you, Stan I have not done well designing multi-band
> Yagi's although I have not tried doing so with AutoEZ. I would be
> interested in seeing your WEQ file for this. Hy-Gain uses a large formed
> aluminum element clamp so you might have to make some guesses for
> modeling. Insulated elements are easier.
> >
> > GL
> > John KK9A
> >
> >
> > Stan Stockton K5GO wrote:
> >
> > Dave,
> >
> > This is pretty easy to do. Would probably end up being 3 on 20 and 4 or
> 5 on 15. The difficult part is inputting exactly what the lengths and
> diameters you are going to use for each element. AutoEZ will do the rest
> of the work using one feedline.
> >
> > If you give me the exact lengths and diameters of the first 3 elements
> on your 20m antenna and same info for what you want to use for the 15m
> elements, I’ll do it for you.
> >
> > No 10 meters?
> >
> > Stan, ZF9CW
> >
> > Sent from my iPhone
> >
> >> On Nov 3, 2025, at 11:40 PM, dave arruzza via TowerTalk <towertalk at
> contesting.com> wrote:
> >>
> >> Has anyone successfully added, non trap, 15 meter elements to a 204ba.
> >> 73
> >> Dave
> >> W1CTN / NC4DARADIO GASTONIA203-906-6209
> >
> >
> > _______________________________________________
> >
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> >
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