Towertalk
[Top] [All Lists]

Re: [TowerTalk] Modeling a self supporting tower interaction

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Modeling a self supporting tower interaction
From: Mike Fatchett W0MU <w0mu@w0mu.com>
Date: Tue, 25 Jun 2024 13:01:19 -0600
List-post: <mailto:towertalk@contesting.com>
Math is hard!  LOL

Thanks

W0MU

On 6/25/2024 10:56 AM, Leeson wrote:
From "Physical Design of Yagi Antennas," ARRL 1992, pg. 9-2:

"This problem is resolved in a short paper by Jaggard [D. Jaggard, "On Bounding the Equivalent Radius," IEEE Trans AP, Vol. AP-28, May 1980, pp. 384-388, https://ieeexplore.ieee.org/document/1142336] Jaggard shows that the equivalent radius ae of a noncircular shape must lie between the radii ai and ac of the inscribed and circumscribed circles which geometrically bound the noncircular conductor. Further, he shows that these bounds can be narrowed by the use of radii ain and aout which are the radii of circles of the area A and perimeter P of the cross-section shape of the conductor, ain = sqrt(A/pi) and aout = P/2pi. A satisfactory estimate for the equivalent radius is the mean of the two bounding radii."

A freely downloadable scan of my 1992 book with more details about the equivalent radius of irregular shapes, "Physical Design of Yagi Antennas," is at https://www.dropbox.com/s/hmhkeofz0igrg1e/Physical%20Design%20Of%20Yagi%20Antennas%20D%20B%20Leeson%20V2.pdf?dl=0

73 de Dave, W6NL/HC8L

On 6/25/24 5:40 AM, john@kk9a.com wrote:
To check for interaction, I have done the easy model method of using
a very thick wire for the tower.  Since the tower is triangular and a
wire model is round, I took a wild guess at the wire diameter. I
never thought of matching the surface area.

John KK9A




Jim Lux wrote:

There's two ways to approach the modeling.  The easiest is to model a
"very thick" wire - match the surface area of the tower with the
surface area of the wire.



_______________________________________________



_______________________________________________ TowerTalk mailing
list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk


_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
<Prev in Thread] Current Thread [Next in Thread>