[Top] [All Lists]

Re: [TowerTalk] Guy cable and crimps lifetime

Subject: Re: [TowerTalk] Guy cable and crimps lifetime
Date: Tue, 12 Apr 2011 11:55:56 EDT
List-post: <">>
In a message dated 4/12/2011 6:13:31 A.M. Pacific Daylight Time, writes:

>  I recently collected several rolls of old guy wire from a  local ham 
with the
intention of removing the strain insulators to use in my  tower installa
He told me the guy wire had been sitting in his back  yard for nearly 30
years and had been used in towers from a broadcasting  station (size and
height unknown).

>  While expecting to cut  through rust to remove the insulators I saw that 
cable was clean and  shiny. The insulators are spaced every 11 feet and the
connection at each  insulator is made with a crimped pressed fitting. I
spread the cable  strands apart and it was equally clean and shiny inside.

>  The  cable is hard and inflexible; I can hold out about 1 meter 
and  it won't bend. It is about 4.7mm (3/16" ?) diameter and has 7 strands.
Each  strand is between 1.6-1.7mm in diameter.

>  I began considering  whether the cable could be used as is instead of
removing the insulators  and installing hundreds of U-bolts on new cable
(there are dozens of  insulators on the rolls). 

>  I therefore have the following  questions:

>  1)       What is the lifetime  of steel cable used as guy wire? Is there 
rule of thumb on how often guy  wires should be changed? Should old guy wire
be replaced/not used even if  it appears to be in good shape?

     Interesting question - and I think a new  topic. 
    I understand that when installing a used tower,  commercial standard is 
to use only new fasteners. I would imagine that the  same might be said for 
the guys.
    I've seen guys and towers that were over 30 years  old and the guy 
wires were fine. I've also seen some that were marginal. 
    Commercial tower inspectors use an  instrument that measures rust 
depth. I don't know what it's called.  

2)       Same question as above  for crimped pressed fittings. Does their
holding strength deteriorate with  time? 
    Probably not. The crimps (typically Nicopress)  are usually aluminum or 
brass and thus don't rust like steel does. The  compression of the pressing 
actually fuses the materials together so there's  not much of a chance of 
them separating or oxidation taking place.  

3)       Can someone help identify the cable with  the description given
above? My guying specs call for 3/16" EHS.

Sounds like EHS to me. 

    If you're ambitious, you might want to paint the  guys with cold 
galvanizing paint. Let it soak in and it should give you  several more years of 
life. In any case, they sound usable.
    If you don't have 100% confidence in them,  use new guys on the top 
level (where most of the forces wind up) and the used  ones on the rest. 
Steve    K7LXC


TowerTalk mailing list

<Prev in Thread] Current Thread [Next in Thread>