[TowerTalk] Tips for Modelling swaged antenna tubing sections

[Dave Sublette]

FWIW, I put a length of tubing in that is the average diameter between the
two points of the swage part.  I use a lot of old Telrex elements which are
swaged at the ends.  I have had good luck modeling these with this method.

Dave, K4TO

On Tue, Sep 29, 2020 at 1:01 PM Mark - N5OT <r-emails at n5ot.com> wrote:

> Back when I would model stuff all the time (K6STI's YO) I just put in
> the swaged parts as separate segments that were the correct diameter and
> length as the swaged parts. That does not really compensate for the tiny
> bit of transition from larger to smaller, but my segments were chosen
> arbitrarily to be halfway through that tiny bit of transition (i.e. the
> combined lengths added up to the actual phisical length of the HyGain
> part I was modeling.  I figured no matter how inaccurate my method was,
> it was still better than ignoring the swaged part altogether.
>
> 73 - Mark N5OT
>
>
> On 9/29/2020 11:02 AM, jimlux wrote:
> > On 9/29/20 8:52 AM, Charles Morrison wrote:
> >> No. Outside.
> >
> > So you have a small bump in diameter. Model it as such. Add a short 1
> > segment wire that is the diameter of the swaged part.
> > realistically, if it's a "tiny" part of a wavelength, it's not going
> > to make much difference.
> >
> >
> >>
> >> On Tue, Sep 29, 2020 at 11:49 AM jimlux <jimlux at earthlink.net
> >> <mailto:jimlux at earthlink.net>> wrote:
> >>
> >>     On 9/29/20 8:31 AM, Charles Morrison wrote:
> >>      > Is there an accepted reduction percentage that is used ?
> >>      >    How do you model the swaged portion of tubing ?
> >>      >
> >>      > The published HyGain models do not account for it in a separate
> >>     tubing
> >>      > section, so no hints there.
> >>
> >>     Isn't the shrunkdown part inside another element? If so, it's not in
> >>     the
> >>     circuit.
> >>
> >>
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