[TowerTalk] Anchor placement - Rohn 45G

Jerry W5KP w5kp@swbell.net
Thu, 31 May 2001 06:55:19 -0500


Thanks for the reply, Tom. I'll be using the Rohn 84" long x 5/8" GAR30
type. They have a "hook" in the bottom end, and an eye in the business end,
where there will be a three-hole equalizer plate (initially using only the
end holes, of course). I'm following Rohn specs for the guys, with 1/4" EHS
on top (guy point will be at the corners of the 45AG4 flat top section) and
3/16" EHS for the lower guys, which will be attached to a Rohn guy bracket.
Don't have torque arms, don't think Rohn even sells them any more, and
besides have been told they don't do all that much good anyway. This will
also be my first experience with big grips, so that's another little
learning curve. I hope they work as slick as people say. Is it advisable (or
permissible) to add a cable clamp for insurance near the dead end of big
grips? Have read a couple of scare stories about them suddenly slipping,
don't need that when my old wrinkley butt's up there. I do need to order a
Loos tension gauge, have to do that from Champion, I understand. Hoping to
be able to buy a big sack of small hardware (bolts, PAL nuts, turnbuckles,
thimbles, etc.) from WB0W at HamCom in Dallas in a few days. Still looking
locally for a mast, haven't been able to find anybody yet in the Oklahoma
City area who even knows what SAE 1026 or 1027 2" tubing is, but have only
talked to pipe guys, need to talk to the specialty tubing guys, I guess, or
the race car shops. All I've see so far here is ASTM "A-xxx" specs for
oilfield pipe, vice automotive chassis tubing. Since this is an oil town,
lots of folks have 1-1/2" heavy wall pipe that is 1.900" OD, but the yield
specs on it are only about 30,000 to 35,000 lb, which is about half of what
I understand the SAE stuff is. Of course, you can get it in wall thicknesses
up to 5/8" (would that be a heavy mast or what!). I'll keep looking. I have
a new Yaesu 1000 rotator, but mast and rotor placement are another whole
subject, guess I'll cross that bridge when I get there. Not that big a
project, but not a trivial exercise either, as I'm sure many Talkians know!
The only think left that is a total unknown is how to get holes dug for the
anchors, which will be in 12" of dirt and 2 or 3 feet of sandstone. I think
that part might get ugly.

73, Jerry W5KP

----- Original Message -----
From: <n4kg@juno.com>
To: <TOWERTALK@contesting.com>; <nielsen@oz.net>
Sent: Thursday, May 31, 2001 5:58 AM
Subject: Re: [TowerTalk] Anchor placement - Rohn 45G


> What type of anchors are you going to use?
>
> For my taller towers, I use 2 screw in anchors for each leg,
> the first at 60 ft out holds the guys at 30 and 60 ft.
> The second at ~90 ft out holds the upper guy / guys.
> I use 1/4 inch guys for the top set on 90 and 130 ft towers
> and 3/16 inch guys for the lower sets with 30 ft spacing.
> With wider spacing, it would be wise to use 1/4 inch
> guys at all levels.
>
> If you ever want to use a long mast and stacked rotary
> antennas (a tribander and 2L40 is a powerful combination),
> then place the top set of guys as close to the top as possible.
> The Rohn drawings ASSUME a microwave dish on the top
> section...not exactly what you want to use for an amateur
> antenna plan!
>
> BTW, if you put your tribander at 90-100 ft, it would be good
> to add another around 40 ft for high angle coverage.
>
> de  Tom  N4KG
>
>
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