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[TowerTalk] Multiple guy anchors

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Subject: [TowerTalk] Multiple guy anchors
From: (Don Moman)
Date: Thu, 23 Dec 1999 10:15:31 -0700 (MST)
Well, I sure think it is.  I've done similar things here on some of the
towers for both the reasons you mention.  I changed my stacking plans when
the 48 foot boom OWA designs came out, so I moved the top set of guys out
another 50 feet by turning in another set of screw anchors. On some of the
other towers I have installed two extra screw anchors directly beside (one
on each side) the original anchor.  Belt AND suspenderss, you know....

On a single guy anchor corroding thru - NEVER have a DC path from one rod
to another guy point or tower base.  You should have at least one big
insulator in series with each guy, or one for all.  This prevents current
flowing between these points, an especially likely situation if you have
the points in widely different types of soil or wet/dry etc.  A rough rule
of thumb is "20 lbs per amp year". You can see that even a few ma flowing
for several years could remove enough metal to be a concern.  An
especially bad scenario is a cement base for your anchor with a thin layer
of dirt over top - this concentrates all the corrosion in those few

73 Don

On Thu, 23 Dec 1999, Pete Smith wrote:

> I've been thinking that as long as I'm replacing my top guys anyway (on 100
> ft. of Rohn 25), it might be a good idea to get some good-sized AB Chance
> screw anchors and make up a second set of anchor points a few feet further
> out than my original ones (which now handle all 3 guy sets).  Seems to me
> that this would flatten the angle of the top guys slightly, making for
> easier stack turning, but more important, would eliminate a potential
> single point of failure.  I have visions of a guy anchor rod corroding
> through or something similar, leading to the entire thing going down like a
> tree -- a scenario that separate anchors could avoid.
> What do people think -- is it worth doing?  
> 73,  Pete N4ZR

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