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Old June 10th 08, 09:08 PM posted to rec.radio.amateur.antenna
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Default How to calculate wind load area?

Can anyone explain to me how to calculate the wind area for an
antenna? I assume you combine the square footage/inches on what would
be the largest side, then factor in any round parts... Which if I
understand correctly, you do by taking the sum of those round parts
and multiply by 2/3? So then you add that with the square parts and
that's your wind load area? I'm sure I'm probably missing something.

Thanks,

Dave

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Old June 11th 08, 12:11 AM posted to rec.radio.amateur.antenna
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Default How to calculate wind load area?

Dave,
That's probably as accurate as needed. Probably the average person
just figures the 'square' area and leaves it at that. At least that
would give you some 'wiggle room' when figuring what support is
needed. If you're talking about graded classroom stuff, you're on
your own! Been too long for me...
- 'Doc


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Old June 14th 08, 08:14 PM posted to rec.radio.amateur.antenna
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Default How to calculate wind load area?

On Jun 10, 4:11 pm, wrote:
Dave,
That's probably as accurate as needed. Probably the average person
just figures the 'square' area and leaves it at that. At least that
would give you some 'wiggle room' when figuring what support is
needed. If you're talking about graded classroom stuff, you're on
your own! Been too long for me...
- 'Doc


Thanks, you've got a point there. Better to error on the safe side.

Dave
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Old June 15th 08, 02:03 AM posted to rec.radio.amateur.antenna
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Default How to calculate wind load area?

Dear Dave (no call):

If you wish to get down to details, the standard for most of such
calculations can be found in ANSI/TIA standard 222G. Put 222G and wind - or
the like - into Google. A copy of the standard itself is expensive.
Earlier versions were quite inexpensive.

For low towers and antennas, especially in an urban or built-up area,
simple is usually good enough.

Regards, Mac N8TT
--
J. McLaughlin; Michigan, USA
Home:
"Dave99" wrote in message
...
On Jun 10, 4:11 pm, wrote:
Dave,
That's probably as accurate as needed. Probably the average person
just figures the 'square' area and leaves it at that. At least that
would give you some 'wiggle room' when figuring what support is
needed. If you're talking about graded classroom stuff, you're on
your own! Been too long for me...
- 'Doc


Thanks, you've got a point there. Better to error on the safe side.

Dave



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Old June 16th 08, 04:34 PM posted to rec.radio.amateur.antenna
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Default How to calculate wind load area?

J. Mc Laughlin wrote:
Dear Dave (no call):

If you wish to get down to details, the standard for most of such
calculations can be found in ANSI/TIA standard 222G. Put 222G and wind - or
the like - into Google. A copy of the standard itself is expensive.
Earlier versions were quite inexpensive.

For low towers and antennas, especially in an urban or built-up area,
simple is usually good enough.

Regards, Mac N8TT


Depends on what your regulatory environment is, too...

A 50 foot tower out in the middle of a 160 acre field will typically
require less analysis to meet the local rules than a 100 foot tower on
5000 ft suburban lot.


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Old June 16th 08, 06:53 PM posted to rec.radio.amateur.antenna
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Default How to calculate wind load area?

Jim Lux wrote:
"Depends on what your regulatory environment is."

Yes, and I think manufacturers will provide projected areas and
windloading of antennas and supporting structures.

Best regards, Richard Harrison, KB5WZI

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Old June 16th 08, 10:50 PM posted to rec.radio.amateur.antenna
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Default How to calculate wind load area?

Jim Lux wrote in
:

....
Depends on what your regulatory environment is, too...

....

Regualtory environment? See http://www.users.bigpond.com/vk3bjm/gallery.htm
.. The best shots are on the second last row. Mind you, Barry has a good
signal!

Owen

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Old June 17th 08, 05:26 PM posted to rec.radio.amateur.antenna
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Default How to calculate wind load area?

Richard Harrison wrote:
Jim Lux wrote:
"Depends on what your regulatory environment is."

Yes, and I think manufacturers will provide projected areas and
windloading of antennas and supporting structures.

Best regards, Richard Harrison, KB5WZI

I think the OP was looking at an old antenna for which there is no mfr data.
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Old June 19th 08, 07:28 PM posted to rec.radio.amateur.antenna
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Default How to calculate wind load area?

Thanks for the help. Actually, I built a monitoring antenna and was
just trying to figure out the basic wind area. So it's not critical or
anything, I was just curious.

Dave
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Old June 19th 08, 08:07 PM posted to rec.radio.amateur.antenna
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Default How to calculate wind load area?

Dave99 wrote:
Thanks for the help. Actually, I built a monitoring antenna and was
just trying to figure out the basic wind area. So it's not critical or
anything, I was just curious.


Thin rods are kind of tricky.. they have a drag that is much more than
one would expect from their cross-sectional area, depending on the
diameter and wind speed (i.e. the Reynolds number). Cd could be
anywhere from 0.4 to almost 2.0

(this is the aerodynamic curse that afflicts old planes using exposed
wires as structural members)



Dave



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