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Re: [TowerTalk] Guy Cable

To: <eric@k3na.org>
Subject: Re: [TowerTalk] Guy Cable
From: "W3YY - Bob" <w3yy@cox.net>
Date: Thu, 15 Mar 2007 23:03:01 -0000
List-post: <mailto:towertalk@contesting.com>
Eric -

You wrote 

>W3YY reported he has used aircraft cable for guy wires.  Sure, it's
possible.  But that's not what aircraft
>cable was designed for.  One can use needlenose pliers to punch a hole in
the top of a paint can, too...
>or a screwdriver to chisel out some wood.  But aircraft cable IS more
stretchy than 7-strand wire rope under
>load.  That extra stretch may not be a problem at one installation, but
could be a problem at another. 

Eric, I consider you a friend, but that was a real public cheap shot.  If
you want to insult me, please do it off the reflector.

I'm simply trying to help others consider some options that would benefit
them.  I have no argument with the suitability of 7x19 EHS for guys, but I
think there are alternatives that others might find useful.  

In fact, I consider 7x19 galvanized cable to be not a "pair of needlenose
pliers to punch a hole in the top of a paint can", but a superior substitute
for 7-strand EHS.  I wouldn't have been using it for 30 years if I had
problems with it.  Now you, and anyone, can certainly dispute that, but
let's do it without insulting comments.

73, Bob - W3YY


-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Eric Scace K3NA
Sent: Thursday, March 15, 2007 12:41 PM
To: K7LXC@aol.com
Cc: towertalk@contesting.com; wc1m@msn.com
Subject: Re: [TowerTalk] Guy Cable

   "Wire rope" is also a technical term used in the rigging industry.  
It covers all forms of steel cable that have been discussed in this email
thread, including "aircraft cable".

   Choosing a wire rope design for cranking up/down a tower is different
from choosing a wire rope design for guying a fixed tower.  These are
different applications that have different requirements.  Choosing the right
wire rope for cranking up a tower involves a lot more tradeoffs (rope
material, sheave material, sheave diameter and cross-sectional shape, rope
construction, rope core choice, etc).  The tower manufacturer's engineering
team should have evaluated these trade-offs in selecting the type of wire
rope used in a specific tower.  Why second guess?

   Guy cable does not need to bend and straighten as it passes around the
sheaves of pulleys.

   W3YY reported he has used aircraft cable for guy wires.  Sure, it's
possible.  But that's not what aircraft cable was designed for.  One can use
needlenose pliers to punch a hole in the top of a paint can, too... 
or a screwdriver to chisel out some wood.  But aircraft cable IS more
stretchy than 7-strand wire rope under load.  That extra stretch may not be
a problem at one installation, but could be a problem at another.

   K7LXC's prime directive applies.

on 07 Mar 14 09:44 K7LXC@aol.com said the following:
>  
> In a message dated 3/14/2007 4:36:06 A.M. Pacific Daylight Time, 
> towertalk-request@contesting.com writes:
>
>   
>>  My understanding is that EHS is "galvanized steel cable",  which is 
>> not the
>>     
> same as wire rope. 
>  
>     Rope is "a strong, thick line or cord, commonly  one composed of 
> twisted or braided strands of hemp, flax, or the like, or of  wire or
other material".
> And technically, it's only cordage above one inch in  circumference 
> and below 10 (bigger-around than that is a cable).
>  
>     Wire rope is a generic term used to describe just  what it is. In 
> amateur circles we tend to use several different terms for the  same 
> thing; e.g. guy wires, guy cables, etc.
>  
>   
>>  While they might have the same breaking strength,  other
>>     
> characteristics may be quite different, such as abrasion  resistance.
>
>
>     Umm, I'm not sure about the abrasion resistance  but each wire 
> rope is characterized by the material, its lay (either right or  
> left), the number of strands and the number of strand bundles that 
> make up the  completed wire rope; most crank-ups use 7x19 wire rope 
> because all of the  small strands make it easily bendable and flexible 
> so it can pass  over pulleys many times without any damage.
>
>   
>>  Rohn specs call  for EHS, not wire rope. I wouldn't fool around with
>>     
> anything
> other than  what the spec calls for.
>
>
> Yep - the LXC Prime Directive still applies: DO  what the manufacturer
says. 
>  
>     BTW there are 7-8 different grades of wire rope  for a given size;
e.g. 
> 1/4" - galvanized, utility grade, stainless steel, EHS,  etc. - and 
> it's really important to use the right grips with the right wire  
> rope. They are NOT interchangeable.
>
> Cheers,
> Steve    K7LXC
> TOWER TECH
>
>   

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