[TowerTalk] DX Engineering 66-Foot Vertical?

[RICHARD SOLOMON]

What I did was to run a small (1/4" dia) Poly rope the length of the vertical.

Epoxied it at the top, pulled on it to apply tension and epoxied the rope to

the bottom.

 

73, Dick, W1KSZ
 
> Date: Tue, 17 Mar 2009 21:59:54 -0700
> From: jimlux at earthlink.net
> To: richard at karlquist.com
> CC: towertalk at contesting.com; K8RI-on-TowerTalk at tm.net
> Subject: Re: [TowerTalk] DX Engineering 66-Foot Vertical?
> 
> Richard (Rick) Karlquist wrote:
> >> What I worry about in that case is oscillation under the right wind 
> >> conditions.
> > 
> >> Roger (K8RI)
> > 
> > After much experimenting, I have learned something about the oscillation
> > problem:
> > 
> > 1. The worst design is a uniform diameter vertical guyed at equal
> > intervals. This is somewhat obvious from physics.
> > 
> > 2. Tapering the diameters is very helpful.
> > 
> > 3. For really flimsy verticals, I guy every 15 feet
> > 
> > 4. Oscillation may not cause immediate failures, but instead
> > the cumulative effects of fatigue will eventually reach the breaking
> > point.
> 
> Particularly with aluminum..(DeHavilland Comets and all that)
> 
> 
> What about wrapping a rope in a spiral around the outside of the element 
> to kill the aeolian vibration (like they use on car antennas these days)?
> 
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