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Subject: Rope or not.... K7LXC's query
Author: Clive GM3POI <clive@gm3poi.prestel.co.uk>
Date: 28-Mar-2001 03:50:54
It seems to me that mechanical resonance must be present in any element from
any source. Therefore if a failure occurs at any wind speed within the
designed specification the only solution is to change that mechanical
resonant frequency, and that can only be done internally without affecting
its electrical resonance. So Manufactures HOW is it to be done.
In my C31 the 10m Director broke at approx' 18" from the boom not a tip.
Visual observation clearly shows rapid movement of the 10m elements at
higher wind speeds. Clive GM3POI
----- Original Message -----
From: "Pete Smith" <n4zr@contesting.com>
To: <force12talk@qth.com>
Sent: Wednesday, March 28, 2001 3:11 AM
Subject: [Force 12 Talk] Rope or not.... K7LXC's query


> Seems like a fair question. I'm not aware that existing mechanical design
> software addresses the question of resonance, fatigue cracking, etc. How
> can Force 12 be sure that thin end sections of elements will not fail
under
> high wind stress over a period of time? I'm not surprised that this
> problem would turn up first in the D or H models, given the extreme
> conditions they are designed for and the relatively small number of
> antennas built to these specs.
>
> Rope damping may not be the answer, but I'm not persuaded that the
> designers necessarily have all the answers either.
>
> 73, Pete N4ZR
> Contesting is!
>
> The World Contest Station Database
> is waiting for your input at
> http://www.qsl.net/n4zr
>
>
>
>
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This Thread
  Date   Author  
* 28-Mar-2001 Clive GM3POI
27-Mar-2001 Greg Gobleman
27-Mar-2001 Pete Smith
This Author (Mar-2001)
  Subject   Date  
* Rope or not.... K7LXC's query 28-Mar-2001