All, the OUARC will have a much stronger mount for its replacement
Bencher 3X10 antenna for the NWC spire. I believe that we have a 2 inch
O.D. mast. Can anyone verify that?
73,
Kim N5OP
-------- Forwarded Message --------
Subject: RE: OU ARC
Date: Mon, 11 Oct 2021 15:29:57 -0400
From: Tim Duffy <[log in to unmask]>
To: 'Kim Elmore' <[log in to unmask]>
Kim Elmore, Ph
Hello Kim:
I just finished a meeting with our engineers. We will be designing a
heavy duty mount for your new Skyhawk. It will use our Super Duty
clamps. The plate will use 8 of these:
https://www.dxengineering.com/parts/dxe-hds-200ap
<https://www.dxengineering.com/parts/dxe-hds-200ap> and the plate will
look like one I built for K3LR last week. I think this will be fine.
What size mast are you using?
*From:*Kim Elmore [mailto:[log in to unmask]]
*Sent:* Monday, October 4, 2021 6:13 PM
*To:* [log in to unmask]
*Subject:* OU ARC
Hi Tim,
The Alpha Signa Delta Radio Society (the official name of the OU amateur
radio club) has received a grant from the ARDC for new equipment. Chief
among the items the club will purchase is a new Skyhawk 3X10 to replace
the one that came down. We have yet to retrieve what's left of the
mounting hardware still on the mast, but that's one of the items paid
for by the grant.
We expect to find no fault in the installation or the hardware itself,
but even so we *must* to insure that another one simply will *not* come
down again. When this one fell a surprising amount of damage was done to
the roof of the NWC that was found only later when the leaks became
serious. What can DXEngineering do to strengthen the mounting system?
From what we've seen so far, it appears that the U-bolts fatigued and
ultimately failed. Can they be made larger and out of a stronger
material? We've become pretty sure that because of the nature of the
building there is extreme turbulence at the antenna height consisting of
eddies that are on the scale of the antenna itself. We originally had a
3 el SteppIR up there that was completely destroyed by the turbulence at
the antenna height. Eddies on the scale of the antenna itself are
probably the worst possible combination from a structural standpoint.
It's up just short of 200 ft and so the wind for the most part never
stops up there and there's quite a vertical gradient in the wind speed
from ground level up to the top of the building, especially at night.
When we put up the new antenna, we'll use the permanent (red) LocTite on
all the hardware (we used the blue stuff last time) and we'll require
the tower crew to provide photographic evidence that it was applied.
What can DXE do to make the mount stronger for our application?
73,
Kim N5OP
--
Kim Elmore, Ph.D. (Adj. Assoc. Prof., OU School of Meteorology, CCM, PP
SEL/MEL/Glider, UAS, N5OP, 2nd Class Radiotelegraph, GROL)
/“Listen, it's too big a world to be in competition with everybody else.
The only guy I have to get better than is who I am right now.” – Col.
Sherman T. Potter, 4077 M.A.S.H./
--
Kim Elmore, Ph
Kim Elmore, Ph.D. (Adj. Assoc. Prof., OU School of Meteorology, CCM, PP
SEL/MEL/Glider, UAS, N5OP, 2nd Class Radiotelegraph, GROL)
/“Listen, it's too big a world to be in competition with everybody else.
The only guy I have to get better than is who I am right now.” – Col.
Sherman T. Potter, 4077 M.A.S.H./
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