John,
I have no idea. What I do know is there is not a lot of wind load on a 60 foot
tower with no antennas on it and that it would take a tremendous amount of
force to break a single four inch long 1-1/8 inch diameter solid fiberglass rod
in two pieces if held tightly on either end.
I'm not an engineer, but I assume in the case of three of those rods in the
three tower legs that one of them can't break without all three breaking and
would also assume those solid rods would be harder to break than it would be to
collapse the three thin walled steel tubes used in 25G legs.
I wonder what the side pressure is at the base of 60 feet of free standing 25G
in a 60 mph wind?
73...Stan, K5GO
Sent from my iPad
> On Sep 2, 2014, at 7:58 PM, <john@kk9a.com> wrote:
>
> Your fiberglass inserts were amazingly strong to hold up 60' of freestanding
> Rohn 25g! I would not try that using a standard base. Are there different
> strengths of fiberglass material?
>
> John KK9A
>
> To: "w2ttt@att.net" <w2ttt@att.net>
> Subject: Re: [TowerTalk] [Bulk] Re: tower insulators
> From: Stan Stockton <wa5rtg@gmail.com>
> Date: Mon, 1 Sep 2014 23:46:42 -0500
>
> Gordon,
>
> No, sorry for misunderstanding.
>
> Here is what I said regarding the 3/8 rod...
>
> "After seeing the towers bend in about a. 60 mph wind, I used 3/8 fiberglass
>
> rod to guy them to small, homemade anchors - rod welded to a short piece of
> angle. Each anchor is in about a bag of Quickcrete."
>
> The towers were previously unguyed. I believe the inside diameter of Rohn
> 25G
> legs are around 1.125 and that is the diameter of the rods that insulate one
>
> section from the other. - of course with holes drilled to accept the normal
> sized bolts. Then I also have a fiberglass plate that spans the joint,
> attached above and below the splice with galvanized U bolts.
>
> What K8LX understood is correct, and yes, the fiberglass rod I used is very
> strong stuff. I got it from a company that makes those long rods with
> galvanized fittings on either end for the utility companies - the ones that
> are
> rated for about 20,000 pounds in a straight pull. The fiberglass rod was
> 1-1/4" diameter and I had it turned down on each end of maybe 12 inch long
> pieces
>
> The towers are guyed at about the 25 foot level with the 1.125" rod in the
> legs
> and the 3/8 fiberglass rod for guy wires and the fiberglass plates that span
>
> the joints. I am not a bit worried about the 35 feet above the guys, given
> that the towers survived some big winds over about 8 years with no guy wires
> at
> all.
>
> I looked, and there is a photo under low band antennas at k5go.com
>
> 73...Stan, K5GO
>
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>
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