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K7LXC@aol.com wrote:
> In Statement #1 you say " The flat projected areas will."
>
> In Statement #2 you say "we get to use the larger areas contained in the
> oval outlines of the Rohn diagrams".
>
> Aren't these contradictory? My question still remains - "WHICH figure do
> we use to determine Rohn antenna load capacities vis-a-vis amateur yagis?"
>
> Cheers, Steve K7LXC
>
Hi,Sigh, this can be difficult to explain!Ok , Both of the oval and rectangular
values in the Rohn drawings are projected
area.
The Oval one is larger, because the round members have less drag, hence, less
load, hence, lower "effective area". The larger oval value generates the same
applied load on the tower as the rectangular one.
If the antenna is made with round tubing, use the oval area. If it is made from
box tubing, use the rectangular area.
Is that any better?
73, Kurt
--
YagiStress - The Ultimate Software for Yagi Mechanical Design
Visit http://www.freeyellow.com/members3/yagistress
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K7LXC@aol.com wrote:
<BLOCKQUOTE TYPE=CITE> In Statement #1 you
say " The flat projected areas will."
<P> In Statement #2 you say "we get to use
the larger areas contained in the
<BR>oval outlines of the Rohn diagrams".
<P> Aren't these contradictory? My question
still remains - "WHICH figure do
<BR>we use to determine Rohn antenna load capacities vis-a-vis amateur
yagis?"
<P>Cheers, Steve K7LXC
<BR> </BLOCKQUOTE>
Hi,Sigh, this can be difficult to explain!Ok , Both of the oval and rectangular
values in the Rohn drawings are projected
<BR>area.
<BR>The Oval one is larger, because the round members have less drag, hence,
less
<BR>load, hence, lower "effective area". The larger oval value generates
the same
<BR>applied load on the tower as the rectangular one.
<BR>If the antenna is made with round tubing, use the oval area. If it
is made from box tubing, use the rectangular area.
<BR>Is that any better?
<P>73, Kurt
<BR>
<P>--
<BR>YagiStress - The Ultimate Software for Yagi Mechanical Design
<BR>Visit <A
HREF="http://www.freeyellow.com/members3/yagistress";>http://www.freeyellow.com/members3/yagistress</A>
<BR> </HTML>
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