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[TowerTalk] rope in elements

To: <towertalk@contesting.com>
Subject: [TowerTalk] rope in elements
From: n4kg@juno.com (n4kg@juno.com)
Date: Mon, 26 Mar 2001 22:28:45 -0600
Not for long !   As soon as the hawks realize the plastic owl
isn't moving  (i.e. isn't living) they will reappear, just as the
woodpeckers who liked the soft cedar panels of my house
reappeared after figuring out that my plastic owl was not real.
Same story for rubber snakes and aluminum pans.
A  REAL dead bird, however, did have a lasting effect.

Tom  N4KG


On Mon, 26 Mar 2001  "Jim McDonald" <n7us@arrl.net> writes:
> Hawks have taken a liking to my Force-12 Magnum 340.  Sitting on the 
> boom doesn't worry me, but that's not the case with the elements. 
Would 
> a plastic owl keep them off?
> 
> Jim N7US
> 
> -----Original Message-----
> From: owner-towertalk@contesting.com
> [mailto:owner-towertalk@contesting.com]On Behalf Of K7LXC@aol.com
> Sent: Monday, March 26, 2001 8:28 AM
> To: ve3tu@rac.ca; towertalk@contesting.com
> Subject: Re: [TowerTalk] rope in elements
> 
> 
> In a message dated 3/23/01 3:13:22 PM Pacific Standard Time, 
> ve3tu@rac.ca
> writes:
> 
> > I was wondering if any one on the reflector has any
> >  comments about the pros and cons of putting rope in beam
> >  elements. It seems that the tips are always the first part
> >  of the beam to self eject. I tried an elements with and
> >  without rope and there was a slight reduction in vibration
> >  with the rope (spinning an element by hand) es just
> >  wondering if there is an other benefit.
> 
>     With conventional yagi design, the element taper was gradual. 
> The
> reasoning was that you make the elements stiff and strong. Since the 
> element
> pieces were all 'about' the same size, they would self-resonate in 
> light
> winds. Since the result was that the elements would spend a LOT of 
> time
> vibrating, they would eventually crack and break or shed pieces. The 
> rope in
> elements was a successful way to dampen this light wind vibration.
> 
>     Force 12 changed this paradigm when they came out with their 
> aggressive
> taper schedule. The element starts out reasonably fat and tapers 
> real quick.
> This eliminated the element vibration and the need for rope in the
> elements -
> two very worthwhile goals. So now the thinking is "bend like a 
> willow"
> rather
> than "break like an oak". It also has been shown to be useful in 
> icing
> conditions - the elements droop like crazy with an ice load but then
> straighten right out with no damage when the ice melts.
> 
> Cheers,     Steve     K7LXC
> Tower Tech
> 
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