Dick:
You're lucky, I had a friend from the Boy Scouts who
owned his own excavating business and owed me a favor
so he sent a backhoe over one day to dig by 4x4x6 base
for my WT51 TriEx crankup back in the early 90s.
Unbeknowst to me this area of North Texas between
Dallas and Fort Worth is impregnated with undergound
springs and the 6 foot hole had filled with water by
the next morning. I even had the city water
department come out because I thought we had a leak
someplace. They pumped out the hole and then showed
me all of the small springs seeping water on the sides
of the hole.
Ended up hiring a professional tower installer who
hand dug the whole thing, set the base and poured the
concrete, all within 12 hours. Even then you could
see the "springs" seeping in the hole, but the
concrete went in fast enough so the water was no
problem.
What we couldn't figure out though was the early 1960s
Chevrolet pickup truck steering wheel we found at 6
feet below ground and still in pretty good condition
execpt for a little bit of rust. I checked with the
city again and they assured me this housing
development (no HOA or deed restrictions) wasn't built
on a landfill in the early 1980s. Kept looking for
Jimmy Hoffa, but never found anything other than some
very hard and solid pieces of sandstone we had to dig
out by hand since we couldn't get them to break off by
pounding them with a sledge.
We had to pump the concrete from the street since the
driveway wasn't rated for supporting a mixer truck.
Also, we had all the dirt from the first hole pushed
back into it so no neighborhood kids fell in who
couldn't swim. I didn't have lifeguards on
duty.........
FYI, since I put my tower up they have found this
entire area of North Texas is located on a big
geologic formation called the Barnett Shale and is
apparently full of natural gas. They're drilling
around here like crazyand some folks are making $$$$
from the drilling rights, royalties, and flat out just
selling their property. Even the colleges and
universities are allowing drilling on their campuses.
You drive along the north boundaries of DFW
International Airport and I bet there are or were at
one time six drilling rigs that hit big underground
gas pockets. I think they had to change the landing
pattern on the north end of the main N-S runways
because of the drilling rigs there, even though they
wereall lit up and had big orange flags on top.
Noticed recently that where one rig had been there is
now a "Christmas Tree" control device to feed the gas
into a pipeline.
73 de Tom, WW5L
--- Dick Green WC1M <wc1m@msn.com> wrote:
> I live in West Central NH, a semi-rural area. The
> cost of my Rohn 55G base
> and guy anchor footings was about $2,000. However, I
> built to the Rohn 110
> MPH spec, so the guy anchor footings are twice the
> size of the typical 90
> MPH spec used by hams.
>
> The cost above includes equipment and labor for
> excavation, backfill,
> concrete, shuttling concrete from the driveway to
> the tower site, rebar (cut
> to order) and form. I participated heavily in
> squaring up the holes,
> building the rebar cages and building/removing the
> base form. It was a lot
> of back-breaking labor for me, even with excavation
> equipment run by hired
> professionals and a helper for the other tasks. The
> tower is on a steep
> hill, which made my personal labor expenditure all
> the greater (lots of
> climbing down and up.)
>
> The concrete alone cost nearly $800, due not only to
> the 110 MPH spec, but
> also the realities of digging deep holes in ledgey
> terrain with a backhoe.
> It's very difficult or impossible to dig perfectly
> squared holes exactly to
> Rohn spec with excavation equipment. You end up with
> larger, more irregular
> holes, which require more concrete.
>
> I sometimes wonder what it would have cost had I
> outsourced 100% of the job.
> I think it would have been $500-$1,000 more.
>
> These costs were a relatively small fraction of the
> overall cost of building
> the tower and populating it with four antennas and
> four rotors, even though
> I did all the climbing myself. In retrospect, I
> probably should have hired a
> contractor to do a turnkey job on the base and
> footings.
>
> 73, Dick WC1M
>
> > Just wondering the amount one might expect to pay
> for installing a
> > base section and the variations around the
> country
> >
> > Rohn 55G requires 5.3 cubic yards of cement, with
> rebar and gravel.
> > The cost of digging the hole (back too far gone at
> this stage)
> > and the cement job is estimated to be about
> $1,400.
>
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