[TowerTalk] Long span lanyard for wire antenna

[john at kk9a.com]

I was thinking of 1/4" or 5/16" Phillystran which weighs 0.018 or 0.033 pounds/ft.

John KK9A
 

From: Haring family [mailto:dcharing at gmail.com] 
Sent: Wednesday, April 21, 2021 3:08 PM
To: john at kk9a.com
Cc: TowerTalk at contesting.com
Subject: Re: [TowerTalk] Long span lanyard for wire antenna

You'll always have sag... less sag, with more tension...

Here is a calculator, with both ends at the same elevation. Using 1/2" Phillystran for a 350' span, you have something like 23' of sag with a 100# tension in the cable. You want very little sag? Better be prepared to have significant lateral stress, and make sure your anchors and guying system is designed for it. I didn't look any further for a calculator which would allow uneven end heights...

https://www.spaceagecontrol.com/calccabl.htm?F=100&a=350&q=0.15&g=32.18503937&Submit+Button=Calculate

regards,

Dave N3AC

On Wed, Apr 21, 2021 at 12:48 PM <john at kk9a.com> wrote:
I am not a mechanical engineer but I am guessing that if he uses  
Phillystran and allows for perhaps 10' of sag there is not a lot of  
tension on the cable.  Rope may be worse if it gets wet and heavier.

John KK9A


>
> On 4/21/2021 9:04 AM, Steve K8LX wrote:
>> Rather than be tempted to use high enough tension where turnbuckles  
>> are needed, let it sag a little, give up a few feet of height -  
>> your tower guy systems will appreciate it.
>>
>> -Steve K8LX



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