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Re: [TowerTalk] Antenna & Tower Wind Load Ratings

Subject: Re: [TowerTalk] Antenna & Tower Wind Load Ratings
From: Kurt Andress <>
Date: Thu, 15 Jun 2017 21:12:14 -0700
List-post: <>
Jim Lux,
Thank you for contributing to this discussion!
I don't think we agree about everything said, but that is quite ok!
All I intended to do with my initial post....was to remind those on this reflector now, that what I told them was wrong a couple of decades ago, is still wrong! I'll leave sorting it all out to all you Stellar Experts that chose to take up the challenge...... I would warn everyone to not try to outsmart the EIA/TIA-222 Standard, we aren't NASA or Boeing, what happens on towers near the ground, is not what happens up at 35,000 ft for Roger, K8IA.... One that studies the 222-G mathematics will find out that the the wind pressure gradients go away and become constant at around 400 ft.......the member oscillations that K8IA mentions are due to a phenomenon known as "vortex shedding", that is well documented and happens at rather low wind speeds with the antennas we use, when insufficient element taper schedules are present to prevent all of the individual element members to go into oscillations together....around the same range of wind speeds they closely share. I have been on lots of towers to see antennas do this, and have designed elements that don't do this.......

I feel no longer qualified to hang with all the tremendous Cerebral & Pundit brainpower that has been brought to bear here, so I will kindly back out of this. I accomplished what I wanted to do....simply to remind the current TT readers that after ~ 35 years of trying to get people to do these things right, these simple things are still not being done right! Thanks to all that read's up to you to demand technical correctness from your vendors!

73, Kurt, K7NV

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