Mike-
Talk to your local concrete supplier about the mix. If you add more bags of
Portland cement, it will increase the final compressive strength. So you'll
reach a higher strength after the first 7 days. US Tower said I needed 2500
psi concrete on my HDX589. I ordered a 5000 psi mix which should have
reached 2500 psi in the first week. I waited 2 weeks before I removed the
forms anyway.
73,
Steve
N6SJ
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
Patrick Greenlee
Sent: Saturday, November 30, 2013 1:06 PM
To: Mike Reublin NF4L; towertalk reflector
Subject: Re: [TowerTalk] More crank-up questions
Mike, The Portland Cement Association says that standard mixes cure to 90%
of their final strength in 28 days. There is no magic number for 100% cure.
Strength asymptotically approaches its final value and (theoretically)
never quite gets to 100% but surely CLOSE ENOUGH. Depending on your mix and
weather (and moisture etc.) at what point along the way toward 28 days will
it be strong enough for your needs? Unless the strength of your mix is
marginal at 90% you should be OK after 3 weeks or so. Sooner MIGHT be OK
but why set yourself up to regret at your leisure what you might do in
haste. Consider the hassle if you load it prematurely and let that color
your decision.
73 and best of luck to you,
Patrick AF5CK
-----Original Message-----
From: Mike Reublin NF4L
Sent: Saturday, November 30, 2013 9:38 AM
To: towertalk reflector
Subject: [TowerTalk] More crank-up questions
I plan to put up a motorized HG-70 HD, with a 4 element SteppIR and a 7
element M2 6M beam.
Hy-Gain says 1 week for foundation curing, UST says 4 weeks. What's
realistic?
My current guyed tower has a side-mounted G-7 and a couple of vhf verticals.
How best to mount those on the crank-up? I was thinking of hanging the G-7
upside down.
Does this tower have latches, or is the weight on the cables when extended?
What about limit switches or stops?
I'd like to carry over my 80 and 160M 1/4 wave slopers. Is that too much
stress? What about ground continuity top to bottom?
Does the concrete/rebar cage make a Ufer ground? Do I need ground rods in
addition?
73, Mike NF4L
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