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Re: [TowerTalk] Orion 2800 Rotator Cable Replacement

Subject: Re: [TowerTalk] Orion 2800 Rotator Cable Replacement
From: Elliott Lawrence via TowerTalk <>
Reply-to: Elliott Lawrence <>
Date: Tue, 10 Dec 2019 21:05:59 -0800
List-post: <>
This is too much of a stretch. Change the SUBJECT line if you are going to 
hijack the topic!!

> On Dec 10, 2019, at 4:27 PM, Jim Brown <> wrote:
> On 12/10/2019 2:41 PM, Bob Shohet, KQ2M wrote:
>> My non-engineering understanding of wires and stretch is that a given wire 
>> after being subject to variable strength forces over a given period of time, 
>> will stretch only so far before it breaks.  Assuming that that is 
>> conceptually correct, let’s say that we have two wires – Wire A and Wire B.  
>> Wire A has been pre-stretched before being put up and is now compared 
>> against Wire B which has just been put up without being pre-stretched
>> Now we subject both wires to the same forces over the same period of time.  
>> I would expect that going forward Wire A will not stretch as far as Wire B, 
>> but is more likely to break and break sooner under significant force than 
>> Wire B because it has already been pre-stretched.  Wouldn’t this be correct?
>> If this is not correct, can you please explain why?
> It all depends on what you define as a significant force. I use 100# weights 
> at ground level on the ropes on one end of my high (125 ft) dipoles to 
> maintain tension and allow for "give" with tree sway. That's a LOT less than 
> the pulling tension applied by W6GJB's pickup to stretch and break them.
> Hard drawing copper strengthens it significantly; NEC requirements for wire 
> antennas call for either CCS or hard drawn copper for strength (so they won't 
> break and create a potential shock or fire hazard). The stretching we're 
> doing is a first approximation of hard drawing.
> 73, Jim K9YC
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