[TowerTalk] Antenna surface area and wind force

[Alan Braun]

This particular discussion doesn't do much for me personally, but shows why
I like this reflector so well. People talk about useful subjects that are
"on-topic". They can disagree with each other and not get into the flame
wars so common on the DX reflectors. Plus folks come out of the woodwork and
provide expertise you'd be hard pressed to find anywhere else.

Good job guys.

Alan NS0B

----- Original Message -----
From: "Tod - Minnesota" <tao@skypoint.com>
To: <towertalk@contesting.com>
Sent: Sunday, June 10, 2001 3:15 PM
Subject: [TowerTalk] Antenna surface area and wind force


> I am sure that I must be missing something in my reasoning, but drawing
from
> my faint recollection of advanced calculus and/or vector calculus it seems
> to me that the solution to the wind force on an antenna element will be a
> double integral which integrates the wind force vector normal to an
> infinitesimal surface area element over all angles from 0 to pi (0 to 180
> deg) in the vertical plane and 0 to pi in the horizontal plane on the side
> of the element facing the wind source.
>
> Once the equations for the wind force on the infinitesimal surface area
> element are written, it should be possible to write an equation that
> describes the torque generated by that infinitesimal element. (Rotation
> around the mast, tower overturning torque or similar torque of interest).
>
> Additional integrations over all surface area infinitesimals should
provide
> the total torque that is of interest. "Turn the crank and get the answer",
> as one of my calculus professors would often say (usually when I had no
idea
> what the hell he was talking about). His other pet phrase was, "The answer
> is obvious!". He once said this, looked at the equations he had written on
> the board, pondered them, and then left the room for five minutes. When he
> came back he said, "Yes, the answer is obvious".
>
> There may be no simple analytic solution, but I would expect that there is
a
> way to use numerical analysis to get good approximations to the solution.
>
> Fearing that I have made a simplistic mistake in putting these thoughts
> together, I will stand back and let the flaming begin.
>
>
> Tod, KØTO
>
>
>
>
> -----Original Message-----
> From: owner-towertalk@contesting.com
> [mailto:owner-towertalk@contesting.com]On Behalf Of EUGENE SMAR
> Sent: Saturday, June 09, 2001 10:07 PM
> To: towertalk@contesting.com; Stu Greene
> Subject: Re: [TowerTalk] Antenna surface area
>
>
> Stu:
>
>      The area to which I refer is the area of the cylindrical shape of a
> tubular element/boom as seen in shadow behind the element/boom.  This is
the
> area used in all wind force studies I've read over the past couple of
weeks,
> including those by Dick Weber, K5IU.  The area to which you refer is the
> surface area of the entire element, the area of material, as it were,
needed
> to fabricate the element.  This area is NOT used in the computation of
wind
> force.
>
>      The tapering of elements would be accounted for by measuring the
length
> and diameter of each taper segment as above and adding them together.
>
> 73 de
> Gene Smar  AD3F
> -----Original Message-----
> From: Stu Greene <wa2moe@doitnow.com>
> To: EUGENE SMAR <SPELUNK.SUENO@prodigy.net>; towertalk@contesting.com
> <towertalk@contesting.com>
> Date: Saturday, June 09, 2001 9:46 PM
> Subject: Re: [TowerTalk] Antenna surface area
>
>
> >At 09:06 PM 6/9/01 -0400, you wrote:
> >
> >>  Area = L X diameter for the exposed surface of each piece of aluminum,
> >> simple as that.
> >
> >
> >
> >Shouldn't the calculation be L X (Diameter X pi) ?  Or length times
> >circumference?
> >
> >And this doesn't reflect tapering of the elements.
> >
> >
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> >-----
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>
>
> List Sponsor: Are you thinking about installing a tower this summer? Call
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> for information on our fabulous Trylon Titan self-supporting towers - up
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> 96-feet for less than $2000! at 888-833-3104 <A
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>
>
> List Sponsor: Are you thinking about installing a tower this summer? Call
us
> for information on our fabulous Trylon Titan self-supporting towers - up
to
> 96-feet for less than $2000! at 888-833-3104 <A
HREF="http://www.ChampionRadio.com">
> www.ChampionRadio.com</A>
>
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>


List Sponsor: Are you thinking about installing a tower this summer? Call us
for information on our fabulous Trylon Titan self-supporting towers - up to
96-feet for less than $2000! at 888-833-3104 <A HREF="http://www.ChampionRadio.com">
www.ChampionRadio.com</A>

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