I put up a 50ft Rohn 25G tower in 1971 using used 25G sections. I bought Rohn
screw in anchors and used no concrete, but a Rohn BP25 baseplate (no longer
sold). Took
this tower down in1987 everything looked FB, no rust. It
had held a light TA33 with 40 meter conversion kit without any problems. I
then moved to Ohio and reused the tower and anchors until 2010. Again, the
anchors look just fine. Recently put the same 25G back up but added a few
sections and put 5 feet in a 4 X 4 X 5 hole with concrete. Top is now at 73
feet and guyed at 34 and 64 feet using the same anchors. Again no sign of
rust. Do you ever see anchors put in by cable, electric or telephone companies
using concrete, or see them replacing anchors routinely?
73
Dave -N4DB-
On Tuesday, January 7, 2014 8:04 AM, Hans Hammarquist <hanslg@aol.com> wrote:
If I understand you right, the screw anchors should be replaced at about ten
years interval. Needless to say, if something fails due to corrosion or
what-have-you it will break, that's what maintenance is for. The pull-out force
is what it is for a intact screw anchor. It will be less for an anchor damaged
by corrosion. That's there the maintenance come in.
If you check my album:
https://www.facebook.com/media/set/?set=a.10150198503693539.328964.579753538&type=1&l=b4a8463457
there is one picture of some bolt that were holding the tower together when I
received it. They were, obviously not fit for service any longer.
Hans - N2JFS
-----Original Message-----
From: K0DAN <k0dan@comcast.net>
To: Hans Hammarquist <hanslg@aol.com>
Sent: Mon, Jan 6, 2014 4:20 pm
Subject: Re: [TowerTalk] screw anchors (was Welding Rebar)
I have had a screw anchor fail, resulting in the destruction of a 70' tower
plus all antennas and hardline.
This was about 16 years ago, and the tower had been up 15+ years with no
problems. Over time, galvanic action between the soil (thick clay below
about 2' of black dirt) and the steel caused one anchor rod to stretch out
like taffy and eventually snap. This caused a chain reaction of the other
guywires. It was ugly and costly.
Except for a temporary installation, I'd encourage anyone considering use of
screw anchors to install them into concrete and not in direct contact with
soil. YMMV.
73
dan
k0dan
-----Original Message-----
From: Hans Hammarquist
Sent: January 06, 2014 15:00
To: towertalk@contesting.com
Subject: [TowerTalk] screw anchors (was Welding Rebar)
I don't see any problems with screw anchors. Anyone what havae had any
problems with them The one I use are, according to the manufacturer's spec.,
good for a pulll force of 14,400 # in undisturbed,dry sand.
Hans - N2JFS
-----Original Message-----
From: Wayne Kline <w3ea@hotmail.com>
To: Roger (K8RI) on TT <k8ri-on-towertalk@tm.net>; towertalk
<towertalk@contesting.com>
Sent: Mon, Jan 6, 2014 1:51 pm
Subject: Re: [TowerTalk] Fwd: Welding Rebar
I think we all have a few OMG or WTF regarding tower/antenna installation
and
upkeep
Field Day. are a prime example of Elmer's rule ( If it did not fall down
it
was not big enough or high enough )
I personally know of a statin that had 5 towers 4 100' & 1 80' guyed with
3/16
ehs three levels on the 100' and two levels on the 80
all with mono band beams one being a full size 40 meter beam and there
were
screw in anchor's and NO I repeat NO concrete
anywhere . the bases being Rohn 25 hinge plates bolted to 2' X 3' steel
plate
and a three or four rebar's 1/2 dia pounded in the soft wet ground.. last
for
many many many years
YMMV
Wayne W3EA
Date: Mon, 6 Jan 2014 03:26:43 -0500
> From: K8RI-on-TowerTalk@tm.net
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] Fwd: Welding Rebar
>
> On 1/6/2014 12:58 AM, Hans Hammarquist wrote:
> > I believe K2TTT put one tower up using nothing as a base, just the tower
standing on a small plate, resting directly on ground. Yes, it is (was)
guyed.
> Over the years (since 61) I've had 7 towers up using dirt bases. They
> were only 40-50' with one 60 footer, and one 90 footer, all guyed. I
> had a 5L 20M KLM, 6L 15M KLM,(42' booms) and a 7L Wilson 10M Yagi on a
> 39' boom. One was 90' with a Cushcraft ATB34 It's a rather rugged dirt
> base and in solid soil, I'd not hesitate to go 90 feet with 25G, but
> avoid those towers that only have the horizontal bracing.
> http://www.rogerhalstead.com/ham_files/Dirt_Base.htm I'd consult an
> engineer for higher or different soil. I over guyed the 90 footer which
> was a mistake. The extra weight and proper tension of the larger steel
> guys put an excessive vertical load on the tower causing the bottom 3
> sections to bell out where they join, requiring a hydraulic jack to get
> them apart.
>
> 73
>
> Roger (K8RI)
>
> >
> > Dave, am I correct?
> >
> >
> > Hans - N2JFS
> >
> >
>
>
> ---
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