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Re: [TowerTalk] Mast slipping

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Mast slipping
From: <donovanf@starpower.net>
Date: Fri, 20 Apr 2007 22:27:14 -0400 (EDT)
List-post: <mailto:towertalk@contesting.com>
Byron,

Unless you're in an area with no winds, the MonstIR will destroy your
2800 in the first heavy wind.

You should use a much larger rotator such as the largest Prosistel,
or K7NV's prop pitch. You should also replace your 2 inch mast with a
3 inch mast.  A 2 inch mast has inadequate clamping surface for the
large torque developed by the MonstIR.

73!
Frank
W3LPL

---- Original message ----
>Date: Fri, 20 Apr 2007 21:27:01 -0400
>From: "Byron Lichtenwalner" <w3wkr@verizon.net>  
>Subject: [TowerTalk] Mast slipping  
>To: <towertalk@contesting.com>
>
>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,  
>cmsande@gmail.com 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
>
>the 
>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  connection. 
> 
>    The GH controller is very nice but won't do  anything about the basic 
>problem. 
> 
> 
>    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. 
> 
>Cheers,
>Steve      K7LXC
>Champion Radio Products
>Cell: 206-890-4188
> 
> 
>
> 
>
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