[TowerTalk] Guying Material and resonance

[Roger (K8RI)]

Jwpjj at 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
>  
>
>
>
> **************Vote for your city's best dining and nightlife. City's Best 
> 2008.      (http://citysbest.aol.com?ncid=aolacg00050000000102)
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>   


-- 
Roger (K8RI - ARRL Life Member)
www.rogerhalstead.com
N833R (World's oldest Debonair)