[TowerTalk] Insulator Clevis Clarification
donovanf at starpower.net
donovanf at starpower.net
Sat Feb 10 12:55:52 EST 2007
Several Towertalkians asked for clarification on the insulator clevis.
I use the Joslyn J732 insulator clevis, you can find a photo at:
Or use your favorite search engine to search for: Joslyn J732
Attach the insulator clevis to your tower guy attachment hardware. You
may need a 5/16 inch or 3/8 inch shackle to do this. Pass the clevis
bolt through your guy wire insulator. Pass your guy wire (or preform)
through the other hole in the guy wire insulator.
Voila, the tower has only 8 or 10 inches of steel attached to it before
the first insulator, just like an AM broadcast tower installation.
The rated strength of the Joslyn J732 is 20,000 pounds, enough for any
ham tower I've ever seen!
If anyone needs insulator clevises, I have some excess in my junk
box. They can also be ordered by your local electrical hardware
---- Original message ----
>Date: Sat, 10 Feb 2007 11:29:34 -0500 (EST)
>From: <donovanf at starpower.net>
>Subject: Re: [TowerTalk] Seperation?
>To: tower <towertalk at contesting.com>
>You're correct that six feet to the first insulator is likely to cause
>a resonance in the vicinity of 28 MHz in that set of guys.
>However... Frequent energetic guy motion in the wind will damage the
>solution you described.
>The best approach is to add a new insulator near the tower. Here are
>two alternatives to achieve closer spacing:
> - install a new insulator with wire clips (e.g., Crosby clips) as
>near as possible to the tower. This should get you within perhaps two
>feet. But this is lots of work, ugh!
> - a better solution is to use an insulator shackle at the top of
>each guy. These are over sized shackles commonly used on AM broadcast
>and VLF/LF towers to place the first insulator very close to the tower.
>Think of it as a large U-bolt shaped shackle, with a curved forged
>bolt (instead of a straight bolt) across the the end of the shackle.
>The curved bolt passes through the hole in the insulator.
>I have some forged insulator shackles in my junk box that I could ship
>to you if you want to use that easy solution. These insulator
>shackles are 2.5 inches between the legs and 8 inches long (just like a
>U-bolt), and made out of 1/2 inch diameter forged steel. Their
>strength far exceeds the strength of 1/4 inch EHS. They fit any guy
>insulator with diameter of 2.5 inches or less and a hole diameter of
>1/2 inch or more. They fit the common "502 johnny ball" insulator
>Depending on the design of your tower guy attachment, its likely that you'll need a smaller 5/16 inch or 3/8 inch standard shackle to attach
>the insulator shackle to your tower guy attachment.
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