Not sure what model loose Gauge you have Jeff. I have two a PT-1 for 1/8
3/16 and ¼ and a PT-3 for ¼ 5/16 and 3/8
Wayne W3EA
Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10
________________________________
From: TowerTalk <towertalk-bounces@contesting.com> on behalf of Jeff Blaine
<KeepWalking188@ac0c.com>
Sent: Tuesday, May 15, 2018 7:47:01 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Poly rod, Fiber glass rod, Fiber Protrusion rodtension?
Hard to use a Loos gauge on bigger EHS though. I've got 3/8 EHS on my
top guys and when I hold the Loos up next to it, the EHS just laughs and
calls me silly names as the nearly unbendable 3/8 EHS laughes at me...
73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com<http://www.ac0c.com>
On 15-May-18 6:01 PM, Chuck Dietz wrote:
> By the way, most guy lines like this are terminated with about 15 feet of EHS
> guy line so they are protected from fire and intentional harm. The Loos gauge
> will measure the tension on the EHS, not the Poly rod.
>
> Chuck W5PR
>
> Sent from Mail for Windows 10
>
> From: Grant Saviers
> Sent: Tuesday, May 15, 2018 1:54 PM
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] Poly rod, Fiber glass rod, Fiber Protrusion
> rodtension?
>
> I think the idea in different tensions vs height is to generate the same
> horizontal restraining force since that changes with the cosine of the
> guy angle with the ground. i.e a horizontal guy (zero deg) provides
> 100% of its tension horizontally to the tower, and a vertical guy (90
> deg to ground) zero force.
>
> To stay < 10% of break strength, larger guy diameters are used for upper
> guys and need to be stronger since it takes more ultimate strength to
> restrain the tower from sway. The amount of strain (stretch) with high
> wind forces increases the sway so larger guys stretch less per pound of
> tension. (see the K7NV finite element analysis) btw EHS from what I've
> read, even though very high yield strength, does start to stretch
> permanently at about 60% of break strength. So that is the "normal"
> limit of allowable tension. While stretch is only a few percent of
> length when stressed that high, that can change the initial tension.
> After a max wind "event" it is probably smart to check tensions.
>
> So with that in mind, I think the correct tension is what is specified
> for each guy level by the tower manufacturer, independent of the
> strength of the guy. My considerably oversized guys (1/2" Phillystran,
> 25k# break) were specified by the PE at near normal Rohn pretension
> levels. Another limiting factor is the compression yield strength of
> the tower sections. The bottom section has the weight of all the metal
> above plus the vertical component of the sum of all guy forces from
> every guy level.
>
> So if your polyrod break specs are the same or better than 5/16 EHS all
> is well, follow what Rohn specifies for pretension. One small
> difference might be the pretension stretch vs EHS, which is very low.
> Anyway, by tensioning to the Rohn spec that initial stretch is removed.
>
> Since you have a dynamometer, leave the Loos gauge in the toolbox.
>
> Grant KZ1W
>
> On 5/15/2018 9:20 AM, john@kk9a.com wrote:
>> What is the breaking strength of the rod? 5/16 EHS is 11200 pounds and
>> typically you tension it at 10% of breaking strength. I am not sure what
>> diameter Polyrod is. If it is large, measuring its tension with a Loos
>> gauge may be a challenge.
>>
>> John KK9A
>>
>> Ed K5OF wrote:
>>
>> Question: For those that have used what is commonly referred to
>> depending on discussion “poly rod”, “fiber glass rod”, “Fiber protrusion
>> rod”, etc. in lieu of ehs or phillystran what is the recommended tension
>> of said rod for 5/16” rod?
>>
>> I have done quite amount of research both on line and contacting
>> manufacturers and have found nothing that I can use for a reference or
>> make any sense due to the engineering specs the manufacturers provide me.
>>
>> I am not an engineer and cannot figure out what the recommendation would be.
>>
>> I have my current tower project spec’d on ROHN 55G 130 mph at 130 feet
>> 100 % guying (130 feet) and it calls for the lower guys if using EHS
>> spec ¼” at 665 lbs tension per guy and 5/16” at 1120 lbs tension per guy
>> for the upper guys. (3 sets of guys, the two lower ¼”, the final upper
>> at 5/16”)
>>
>> If I am correct if I was using phillystran the tension would be the same
>> based on the same equivalency of that material used to the EHS guy specs.
>>
>> Since I am using this 5/16” “rod" on all three guy levels I want to make
>> sure I do not under or over tension.
>>
>> Rod provided was second hand (no issues, brand new) and was a great
>> deal! I am all set to go up with tower but want to get this right before
>> proceeding further. I have Loos gauges and Dynaometer at my disposal
>> along with everything to get this project up as described above. Hope to
>> get going when I get back from Dayton. From what I have determined so
>> far it is best to tension everything up of course beginning with bottom
>> set of guys to roughly 250 lbs + or -, get plumb and go from there with
>> turnbuckle adjustment and get somewhere in the ball park of a safe and
>> secure tension on final product as we go up to the final set of guys
>> (#3) at 130 feet. 250 lbs is far off from 665 and 1120 but because of
>> the material possibly those tension specs are not in the ball park of
>> EHS or Phillystran? What say the group with any knowledge of using this
>> type of guy material? When I get back from Dayton I am working on
>> getting the tower up with a successful and safe out come? Thanks in
>> advance , if you see me at the Crowne or the venue stop and say hi! 73!
>> Ed K5OF
>>
>> _______________________________________________
>>
>>
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