My opinion is that solid rock is a good thing and you will have no
problems at all. Go with your gut. I can tell you are more nearly to
err on the side of safety than 75 percent of amateurs. I assume this
us a 60 foot tower? I have four rohn 25 g towers for an 80m 4 square
in holes that are about 2x2x2. The base isn't going anywhere.
73...Stan, K5GO
Sent from Stan's IPhone
On Feb 12, 2010, at 8:53 AM, Michael Goins <wmgoins@gmail.com> wrote:
> Guys, I'm needing some help here.
>
> I am installing a HG52SS about 16 miles north of San Antonio in an
> area that is nearly all solid rock and I have two sets of factory
> specs on installation instructions from HyGain. One says (and I'm
> going from memory here, but I'm pretty sure I am correct) 30X30X42"
> for the hole and the other says 42"X42"X5.5 feet for the hole. The
> issue is that under an inch or so of soil here it is virtually all
> solid rock. We are now down about 3 1/2 feet into solid rock on all
> four sides, and it has required a large jackhammer and many hours to
> get there. Assuming the base hole is to be designed for both
> compressive and lateral movement, there is no way it is going
> anywhere, either way.
>
> This location is where I plan to live the remainder of my life, so I
> want it right. The tower will have a 2 el quad on it, and likely
> nothing every bigger than a 3 or maybe 4 el monobander as I have never
> owned a commercial antenna and have always built my own. With it being
> a crank-up, one antenna at a time (especially the 2 el quad) is
> sufficient for me.
>
> My question is: Is this sufficient, considering the ground materials?
> I am highly considering the hole as is, wth a pad one to two feet tall
> around it above ground and tied into the factory rebar base (which I
> will have to cut down and slightly re-do in order to make it fit the
> current hole). With a sufficiently tied-in top pad, the tower cannot
> move in any direction as the above ground part would try to push down
> onto the rock around it, which it cannot do (as the rock 1" and less
> underground is solid).
>
> An engineer is out of the questions as I am an average guy, teaching
> college for what often feels like minimum wage. I am also at least 16
> miles form the nearest possible engineer which would add to the cost
> factor.
>
> Again, this is an amateur tower installation. The load will never be a
> lot as the tower is not rated for a lot of load. It cranks up and
> down, and I monitor the weather here, so it would be lowered when
> conditions suggested that it would be prudent.
>
> I could sure use some opinions.
>
> Michael Goins, k5wmg
> Pipe Creek, Texas
> Fast cars, slow boats, big dogs, and summers off to write
> _______________________________________________
>
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>
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