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Re: [TowerTalk] Rotator clamp help

To: kq2m@kq2m.com
Subject: Re: [TowerTalk] Rotator clamp help
From: Doug Christensen <auriga1usa@gmail.com>
Date: Tue, 24 Sep 2024 09:27:57 -0500
List-post: <mailto:towertalk@contesting.com>
I am using the earliest of the design (same as current) for my OM 2300,
however with a turned aluminum adapter that is 2.5" outside diameter
interfaced into a 3" mast. I have dealt with thunderstorms & one tornado
with winds 80mph+ with no slippage at all. I would attempt to increase the
diameter of your clamped diameter with an adapter of some sort. Q: what
diameter and material are attempting to clamp to? My EPA (Extended Profile
Area) is 13 SqFt. (2 ea M2 yagis) With the tower rated at 25SqFt.
-Doug WB1E

On Mon, Sep 23, 2024 at 9:49 PM <kq2m@kq2m.com> wrote:

>
> Hi Tony,
>
> I have not used a K7NV mast clamp so I can't speak to it's performance.
> But I have been using an Orion 2800 on my top 20 - 5L LJ105CA on a 35'
> boom at 130' for the past 15 years.  In all that time with two
> hurricanes, 1 tornado, and dozens of 80+ mph wind gusts, ice storms,
> Nor'easters, etc. the mast has loosened up only twice.
>
> My antenna is clamped against both the mast as well as the boom and
> balanced for weight at the point at which it is mounted on the boom. I
> believe that the special truss and torque clamp apparatus that I made
> and currently use may have something to do with the clamps longevity as
> it has significantly reduced the rocking of the antenna during periods
> of extremely high winds.
>
> I have not found it necessary to purchase a K7NV clamp but those who
> have used one speak very highly of it.  The main issue is that the mast
> is circular and the stock Orion clamp is more in the shape of a "V"
> which ensures that there is far less than the maximum possible surface
> area of the clamp coming into contact with and gripping the mast.
> Weather, topography, wind and other factors come into play so that no
> two qth's will experience the same set of challenging conditions on the
> clamp.  My qth is particularly windy and turbulent and prone to
> exceptionally violent storms at times so it takes a toll sooner rather
> than later on anything up on my towers.  I'm happy with the performance
> of the stock Orion clamp but all you need is one incident of
> catastrophic clamp failure to ruin your day.   ;-)
>
> 73 and GL!
>
> Bob, KQ2M
>
>
> On 2024-09-23 14:44, Anthony DeBiasi wrote:
> > I am presently using an older M2 Orion rotator.  After 22+ years it has
> > failed and needs replacing.  When I moved to Florida 3 years ago,
> > instead of using the supplied stock mast clamps I purchased a K7NV mast
> > clamp which some of you may be using.  The K7NV mast clamp definitely
> > prevents slippage although in 18 years at my last QTH which was fairly
> > windy the stock mast clamps only slipped once during a hurricane which
> > was easy to correct with the Green Heron RT-21 controller and snugging
> > up the clamp bolts. I should mention the rotator is on a 86’ Tashjian
> > tower that nests to 23’ and is fairly easy to access.
> >
> > I am trying to decide if it would be better to replace the K7NV mast
> > clamp with the stock M2 mast clamps that are more likely to slip.  Why
> > would I considering the change, to possibly put less stress on the M2
> > rotator.  On the tower from the bottom up there is a JK-Mid Tri/40, a
> > 5el M2 6m yagi and on top is a WARC JK1217.  Although I live in
> > Florida, I am located about 15 miles inland and 35 miles north of
> > Tampa. We do get a lot of Thunderstorms in the summer but the wind has
> > been far less than I experienced in Northern NJ and Southern NJ.
> >
> > Would appreciate the advice of anyone who has experience with either
> > the stock M2 clamps or the N7NV clamp. I know you can put a pin through
> > the clamps and mast but I wouldn’t suggest that.
> >
> > 73, Tony K2SG
> > _______________________________________________
> >
> >
> >
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