In a message dated 10/8/98 10:29:41 PM EST, ni6w@yagistress.minden.nv.us
writes:
> Shane NC4SA/KV4I wrote:
>
> > I have just purchased an AB-621/G military surplus antenna mast.
> It
> > consists of 8 individual aluminum sections that all fit into a small
> > portable cage for transporting. They are each about 7+- inches in
diameter
> > and have a thick wall. It is similar to a crankup in design in that you
> > crank it up as you add each section of mast. It is approximately 50 ft or
> so
> > when fully extended and is guyed at 3 different levels. What I need to
> know
> > is how much windload was this mast designed to handle and at what wind
> > speed. I know it wasn't intended for permanent installation and I wish to
> > use it only as a temporary mast(tower) mtn topping in VHF+ contests. I
don'
> t
> > want to overload it. Also was this mast designed to hold microwave
dishes?
> > Just curious as to what Uncle Sam used these for. Thanks de nc4sa
> >
>
> Shane,
> I have one of these up in the back lot with a TH7 on it. It has 3 sets of
> guys,
> and is the cutest little portable rig I've seen. Mine has handled 50 mph
> wind
> with no problems. we'll see what happens this winter. I don't have a manual
> or
> any rating info.
> Have fun with it.
>
> Kurt
>
The AB-621/G was originally designed to handle a 150-lb dish in
100 mph winds. It was designed for temporary (and quick)
installation of microwave dishes to provide point-to-point
communications capability between deployed units, although
I've seen many that seemed to be semi-permanently installed.
I have one in my backyard that currently has a KT34XA on top
of it (55 feet).
When I was stationed in the Azores, I had a TA33 on it
(and despite some comments I've seen, the TA33 is a good
antenna - OK, it's not a TH7 or KT34XA, but it was a lot easier
to haul around the world than they are <g> ) and it survived three years of
winter storms there. I bolted it down on a concrete pad 4 feet by 4 feet
and two feet deep, as well as guying it at three levels. Winter in the
Azores means weekly wind storms of 50-100 mph, with occasional
100-150 mph winds. During a 125+ mph storm, two guy wires snapped,
but everything else held and the next day I just cranked it down and replaced
the broken guys. Never had any other problems with it. When I returned
home, I just built another pad and put the KLM up there. I doubt there's
an easier way to raise a KT34XA.
I have an original manual for this thing. Anyone who is interested in a
copy, please e-mail me direct. I'll check and see what it will cost to
copy and mail it. It's somewhere around 100 pages long and is quite
detailed and interesting.
73, Mike K3AIR (MSgt, USAF, Ret)
BTW, I use one a loos gauge from Champion Radio to tension the
guys. Great little device (thanks, Steve!)
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