Put one in and measure it. Then you know. Everyone is quick to say it's
not enough and to do "what the manufacturer says". What you need to do is
have a safe and practical installation for your tower situation.
I recently helped put up a 100' L&R 20" face guyed tower (2 el 40 on top).
We used grain bin anchors of the type described here - common and easy to
find in the local farm stores. "Real" anchors were quoting a 6 week
delivery time and winter was coming. I wasn't convinced they were enough -
so we screwed two in at each anchor and pulled 5000 lbs on each (front end
loader and a Dillon tension gauge) and nothing moved. And yes they were in
line with the guys.
Yes I'd prefer longer rods and a bigger helix but these will do the job for
now. We can always screw in another backup anchor when available.
I would, however, worry more about two other factors that have not been
mentioned:
1 - the galvanizing -or lack of - on the anchors - some of them are merely
painted and obviously would not last as long in some soil conditions. And
remember you always need at least one insulator in each guy to prevent
differences in ground potentials causing corrosion and early failure of the
anchor rod.
and 2- make sure the eye is not just bent over - it needs to be either
formed or welded shut.
73 Don
VE6JY
On Sat, Nov 14, 2009 at 9:02 PM, Gene Fuller <w2lu@rochester.rr.com> wrote:
> Hi Rex -
>
> Another two cents worth -
>
> A four foot shank sounds a bit short, even though installed at a 50 degree
> angle it still has to pull tthrough 4 feet of earth. Remember that closer
> to the surface the soil is not as compact and would offer less resistance
> than deeper. If, including some of the tower, the effective surface area
> would be at least 10 square feet, at 30 psf wind pressure you would have a
> 300+ lbs horizontal force, which, translated down to a 50 degree guy angle
> would look more like 400-450 + lbs, again, perhaps a challenge for a 4 foot
> anchor rod only 3 feet deep - especially since 30 pfs may be on the light
> side and higher gusts, and a bit of pumping. I agree with Frank - 6 foot
> minimum.
>
> Gene / W2LU
>
> ----- Original Message -----
> From: <donovanf@starpower.net>
> To: <towertalk@contesting.com>
> Sent: Saturday, November 14, 2009 2:10 PM
> Subject: Re: [TowerTalk] New Tower installation
>
>
> Rex,
>
> Four feet is unusually short for a guy anchor. When you set that anchor in
> at an angle, as you must, it will be buried less than three feet below the
> surface. An appropriate anchor should be at least six feet long.
>
> 73
> Frank
> W3LPL
>
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