It is not limestone. It is a rock shelf. I have limestone here in
places, but there are tremendous boulders and several huge rock
shelves. It is in a rock shelf that is absolutely solid, not porous
like limestone.
Guys, I really appreciate the help.
Michael Goins, k5wmg
Professor, Writing
University of Texas at San Antonio
On Sat, Feb 13, 2010 at 6:02 PM, chas <chasm@texas.net> wrote:
> Michael Goins 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
>> Michael Goins, k5wmg
>
>
>
> Mike is trying to burrow into solid limestone which is prevalent all over the
> Edward's Plateau until you get up to Lake Granite Shoals or about 40 miles
> North of Austin when you get into granite.
>
> but from Fredericksburg to the NWest of SAT south to Hondo and back East to
> black gumbo on the East side of I35, it is all limestone.
>
> and if he got two feet into it, my hat is off to him.
> if it were my HG52 sitting on site, I would have flattend off about 4 sq ft
> of base rock, drilled holes for the 1/2" base plate's all thread 1"+ diam
> bolts about 4' long, set the base plate on its double nuts on the bolts in
> their holes and about 4" proud of the rock surface then poured a slab with
> rebar or heavy remesh. let it sit for a couple of days and then hoist the
> base of the tower onto the base plate and bolt it down.
>
> I would call that a done deal for that area of Texas in that sort of ground.
> Then, I would bring in about 12 cubic yds of iron ore from East of Austin
> (look up Camp Swift) and spread that some 4" thick under top soil for a
> ground and radial surface. sod over it and call it done. if you want, lay
> some remesh in the iron ore as you spread it or some 20' sticks of 3/8 to
> 1/2" rebar and hook them up for a ground field THEN spread your iron ore over
> it, then topsoil and put some sod down on it.
>
> my opinion. I have black gumbo with 4 to 6" iron ore on top of it under some
> 4" of topsoil and sod and it is superb for a radial and reflectant field
> under my antennas, vertical or horizontal.
>
> fwiw
>
> 73
>
> chas
>
> --
> chasm@texas.net k5dam Houston, TX
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