[TowerTalk] N1RR's 2014 Rohn 55G 120ft Tower project

john at kk9a.com john at kk9a.com
Fri Jan 3 07:32:19 EST 2014

Did Rohn change their anchor specifications?  I thought the strength of
the anchors used to be in their catalog but I am not seeing it online. 
With that windload and your area you have reason for concern.  You could
always add a second set of anchors.  My closest 15m and 40m beams are
about 16 feet apart and I have no noticeable interaction however my 40m
beam is not resonant on 15m. You should model your proposed installation
to ensure minimal interaction.

John KK9A

To:	towertalk at contesting.com
Subject: [TowerTalk] N1RR's 2014 Rohn 55G 120ft Tower project
From:	 n1rr at comcast.net
Date:	 Fri, 3 Jan 2014 02:56:53 +0000 (UTC)

Hi ! I've got a few questions. Here's what I'm doing: Rohn 55 120ft

I live in Massachusetts near the northeast corner of Rhode Island. It's a 110
MPH zone. I'd classify this as an Exposure B
(Wooded) area.

I put the guy anchors and the base in back in '99. I used GAR30 anchor
rods and
a 10 foot tower section along with
the re-bar that was required at that time at all four locations. Base and
anchor holes were completely filled with
4000psi concrete.

First, I worried about the anchor rods. I wish I had used the larger
GAC3455 or
5655. I was steered to the GAR30's.
What are these limited to ? At what load will they fail at ?
This limit may dictate what I ultimately put onto the tower.

Second, what equalizer plates should be used ? Should I double up on
Will those bolts be adequate ?

My third biggest question might not be appropriate for this list but here
I have a full size Wilson 40M3.
( Yes, I'm planning a star guy bracket at the top. )
How far way should a 15M yagi be from the 40 ?
My guess is 15 to 25 feet.
How far way should a 20M yagi be from the 40 ?
Based on what I've seen in the field, 10 to 12 feet should be plenty here.

Charlie N1RR

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