[TowerTalk] Re: Wind Loading

[EUGENE SMAR]

Bob:

     Thanks for your comments.  One thing from among many that I learned
from DIck's articles is this : The figure 2/3 IS WRONG!  NEVER use 2/3 to
calculate ANYTHING regarding wind loading of a tower.  The correct figure,
according to Dick, is ALWAYS greater than 1, unless you're calculating the
force on a short, wide piece of cylinder, like maybe a coax balun at a
feedpoint.  Then Dick cites drag coefficients of less than unity.

73 de
Gene Smar  AD3F
-----Original Message-----
From: W5LT@aol.com <W5LT@aol.com>
To: SPELUNK.SUENO@prodigy.net <SPELUNK.SUENO@prodigy.net>
Date: Thursday, June 07, 2001 12:36 AM
Subject: Wind Loading


>Hello:
>I commend you on your efforts to correctly calculate the windloading of
your
>antennas.
>I know Dick personally and agree he has do\ne Hamdom a true service by
>publishig the correct ways to handle these problems.
>
>You have independently verified  the major problem that antenna
manufacturers
>DO NOT properly rate their products in a way that is useful in the users.
>Modern tower specs are based on Projected Area, as you have done. The
antenna
>people like to go with the 2/3 adjustment to PA to make the number look
>smaller for marketing reasons.
>When I first met Dick and presented him with a tower loading problem I was
>wrestling with, the first question he asked was how did I calculate the
>antenna wind load? I gave the correct answer, which apparently much
increased
>my credibility. (I said: absent any other data, I would increase the
>manufacturer's number by 50%).
>Good luck and keep doing the right thing.
>73s
>Bob, W5LT



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