[Antennas] Vibrating hollow elements

[Dr. William J. Schmidt, II]

Don't be fooled into thinking that solid elements (or anything else that has 
been offered up on channel) will auto-magically solve this problem.  There 
is a nice mathematical relationship between the mass, length, air (fluid) 
characteristics (speed, viscosity), and the shape (bluff body or air foil) 
and projected area of the elements.  The average guy doesn't know enough 
about fluid dynamics to calculate when a rigid body in a fluid will resonate 
(vibrate)... so you are left to experiment.  Bottom line:  No magic... do 
the experiment.

This will help:  More mass is better.  Bigger diameter and thicker wall 
elements are better.  Stiffer (e.g. solid) is better.

Sincerely,

Dr. William J. Schmidt, II  K9HZ
Trustee of the North American QRO - Central Division Club - K9ZC

Email: bill at wjschmidt.com
WebPage: www.wjschmidt.com

"If computers get too powerful, we can organize them into a committee; that 
will do them in."  -- Bradley's Bromide


----- Original Message ----- 
From: <W0DXZ at aol.com>
To: <antennas at mailman.qth.net>
Sent: Tuesday, September 20, 2005 7:30 PM
Subject: [Antennas] Vibrating hollow elements


> OK I agree, that the Cushcraft maybe a cheaply made, though  well 
> performing,
> antenna.  Now that mine has fallen apart   (second one to do this) I may
> replace it with another brand, unless CCraft comes  up with a free 
> replacement.
> Fat chance.
> So,,, quality antennas, well made, solid elements... anyone  make a solid
> element antenna? I couldnt find any.
> What is the best quality antenna, in the 6 meter 5-6 element  range? Does
> anyone make one that wont vibrate apart? I never had this with a 2M  or 
> 10M
> antenna, why 6M?And why the CCraft, just cause there are so many of them? 
> I never
> had this problem with my 3 ele CCraft 6M beam.
> Suggestions?
>
> Bob W0DXZ
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