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Re: [TowerTalk] rotor question

Subject: Re: [TowerTalk] rotor question
From: "Dennis Vernacchia" <>
Date: Wed, 21 May 2008 09:02:22 -0700
List-post: <">>
The 2800 mast slip problem is well known

here is a piece pof thread from provious discussion

TowerTalk mailing list

The Slipp-Nott has been very effective for both slippage problems with the
Orion M2 2800 mast clamp, as well as mast-to-boom slippage on the MonstIR.

Gary, NØGS

-----Original Message-----
[] On Behalf Of Byron Lichtenwalner
Sent: Friday, April 20, 2007 8:27 PM
Subject: [TowerTalk] Mast slipping

I am in the process of replacing my current rotor with a 2800.  I have a
Steppir MonstIR on a 2" mast.
In the attached note Steve suggests pinning the 2800 mast clamps for
everything EXCEPT the antenna I have.

What would you suggest for the MonstIR ?

Byron, W3WKR

In a message dated 4/17/2007 7:24:54 P.M. Pacific Daylight Time, writes:

>  I saw some old posts by you (circa 2002) stating that you have
> started
pinning the Orion rotators due to slippage.  I have a Orion  RC2800PX
turning a 4L SteppIR and each time we have some wind, by antenna gets  swung
out of position.  This happened again today.

Hiya, Craig --

   It's an Orion design flaw, the mast clamp has 2  problems. First, the
surface where the nuts and bolts seat are dimpled - not  flat. Over time,
the wind motion causes the washers to pound the dimples flat,  thus
loosening up

nuts; then the mast is loose and starts moving. The  problem can be
eliminated by milling or grinding those surfaces flat.

   Secondly only 2-3 teeth of the clamp actually  contact the mast,
resulting in very little clamping. Then you get the teeth  being worn down
as the mast moves back and forth and it loosens some more.

You can re-tighten everything and it'll probably  be good for a couple of
years. For a 4L SteppIR, you can also pin the mast.  Pinning works for
everything except a MonstIR.

>  I have heard good things about the Green Heron Engineering  univeral
rotator controller, which can be re-calibrated in case the mast slips  in
the rotator, however eventually the coaxial cable loop would start wrapping
around the mast if I did nothing more to secure the rotator-to-mast

   The GH controller is very nice but won't do  anything about the basic

   What I do for my customers is provide a new  replacement mast clamp that

uses 6 U-bolts to hold the mast and does NOT slip.  It's $120.00 but if you
re-tighten everything and pin the mast, you'll be good  to go.

Steve      K7LXC
Champion Radio Products
Cell: 206-890-4188

On Wed, May 21, 2008 at 8:45 AM, Joe Giacobello <> wrote:

> Greg, thread locking adhesive, such as Loctite or Permabond types, is
> essential here.  Otherwise I suffer the same bolt loosening problems as
> you have.
> 73, Joe
> K2XX
> Gregg Seidl wrote:
> > I was just doing some of the planned antenna/tower work here lately.Went
> up
> > tower 1 which is 80 feet of Rohn 45.Noticed the mast clamp on the M2
> Orion
> > 2800 is loose AGAIN.It loosens up from the rotor.The clamp is tight on
> the
> > mast.It turns true,I have a flat plate on the top with a bearing and the
> > rotor is mounted 10 feet down.I used the supplied 3/8th bolts with the
> > Ny-lock nuts.It had roughly 18 sq feet of windload on it.
> >     I like the rotor,its tough.But this is the 3rd time they have
> loosened
> > up on me.Am I doing something wrong?Should I use some red Lock-tite,try
> some
> > different bolts/nuts?
> >     Anyone using the new MDS rotor boxes yet.I see they are really made
> for
> > Yaesu rotors.I have a few of them as well.Thought it would be nice to
> have a
> > digital diplay and computer control at a much more reasonable price then
> > Yaesu charges.Plus the box itself is smaller which is nice when your
> shack
> > is small and you keep getting more stuff!I think the Green Heron is great
> > but a bit pricey unless your using some of its unique features.
> >     Now a math/tower question.Been longer then I care to admit that I've
> had
> > to use this kind of math so I thought I'd ask here.I'm putting up a small
> (4
> > times 12 elements) EME array on a short 10 foot tower.The boom lengths
> are
> > 18 feet.I plan on spacing them 10 feet by 10 feet,I know thats not
> perfect
> > but it is easy from an assembly point.That means 5 feet above the
> crossboom
> > and 5 feet below.How high does it need to be off the ground so I can
> point
> > straight up?Should I make be able to point straight up,is that
> desirable?It
> > would be easier to mantain the array but is it worth it.Looking for
> > ideas.Thanks for any help!!  Gregg  K9KL
> >
> >
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