[TowerTalk] Wind survival + load ratings... vs,

[jimlux]

On 11/1/17 11:37 AM, Jim Thomson wrote:
> Date: Wed, 1 Nov 2017 06:06:10 -0700
> From: jimlux <jimlux at earthlink.net>
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] FW: Wind survival + load ratings... vs,
> reality.
> 
> 
> <Overall, hams are probably more comfortable running and believing an
> <electrical model than a mechanical one (more time to become familiar,
> <etc.? or just because the ham tests ask you about electrical stuff, but
> <don't ask you about mechanical stuff)
> 
> 
> 

> ##  Both YS and YM have been around for a loooong time, esp YS.
> They are both within 1% of a megabuck finite analysis eng program.
> Dont kid yourself.  Both  M2 + optibeam have not incorporated any
> safety factor into their designs.   They are both selling smoke.  If they were
> to actually incorporate  a safety factor, M2 would be rating it at  50 mph.
> 

yeah, but unlike NEC, neither is free, nor are there countless articles 
in QST and books on how to run them, so I think it's more about 
"familiarity with the tools"..

I think a lot of hams (at least the ones designing and caring about 
antennas) are a LOT more knowledgable about the electrical 
characteristics than the mechanical ones.

And, of course, EM systems are *linear*, which deforming mechanical 
systems in wind are not. As someone (you?) pointed out, the elements 
deform - it's probably going well beyond the "linear infinitesimal" 
assumption of a simple mechanical model of a bending beam, and that's 
before you get into the complexities of the aerodynamics.

(and of course, there's plenty of misunderstandings about the electrical 
behavior of antennas too...)