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Re: [TowerTalk] Guying Material and resonance

To: Jwpjj@aol.com
Subject: Re: [TowerTalk] Guying Material and resonance
From: "Roger (K8RI)" <K8RI-on-TowerTalk@tm.net>
Date: Wed, 11 Jun 2008 16:27:04 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Jwpjj@aol.com wrote:
> I am getting ready to install 90' of Rohn 25, base section is all  
> done,concrete etc and so are the guying stancheons that are set in concrete 
> as  well. I 
> have the first 10' up and hopefully in a few weeks or so will be ready  for 
> the rest of the installation. My question is what is preferred, steel guying  
> cable or Phillystran cable. One of my concerns ( maybe it should not be) if I 
>  
>   

My preference is the Phillystran. Although it has a tiny bit of stretch 
the catenary with EHS  will allow a lot of movement.  ROHN recommends 
3/16" EHS .  1/4" would add a lot of weight.  Tensioned properly 
resonance is not normally a problem with EHS. Catenary is very shallow 
using Phillystran.
> use steel guying installation, should I be concerned about resonance based on 
>  
> the lengths of guying cable. The tower will have a 4 el steppir at approx 
> 98', 
>  below that there will be a 3 element 40 meter monobander, prosistel rotator 
>   
However, as others have already said, this is a *lot* of load for a 
25G.P/N 25G70D090 gives guying points at 28', 57' and 85' using 3/16" 
EHS anchored 72' out from the base. In CT you have both gusty winds and 
ice.  Were it me, I'd not tackle a load like this with a tower smaller 
than 45G.

73

Roger (K8RI)
> and  fed with LMR400. Will I need to break up the guys? It seems like it 
> would 
> be a  lot of work if I had too or should I just go for the Phillystran and 
> don't be  concerned.  This is my first guyed tower as I have always have had 
> crank  ups. I have seen a lot of pictures that have been on this forum and 
> was  
> wondering what most everyone else uses for guying  their towers. The guying  
> lengths will be as per Rohn specs, 80% of total height to calculate guys  
> lengths. 
>  
> John,  ND1X
>  
>
>
>
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-- 
Roger (K8RI - ARRL Life Member)
www.rogerhalstead.com
N833R (World's oldest Debonair)

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