[TowerTalk] Mast slipping

[donovanf at starpower.net]

Hi Keith,

Suggest u correspond with Kurt, K7NV.  He's the expert on prop pitches these days.

k7nv at contesting.com

73!
Frank
W3LPL

(p.s.  ask Kurt what the owner of SteppIR uses to turn his MonstIR ...)

---- Original message ----
>Date: Tue, 24 Apr 2007 09:30:44 -0500
>From: "Keith Dutson" <kdutson at sbcglobal.net>  
>Subject: Re: [TowerTalk] Mast slipping  
>To: <K7LXC at aol.com>, <towertalk at contesting.com>
>
>Thanks for posting the flaws again.
> 
>Looks like one of the recent improvements is removal of the dimples.  Both
>surfaces (front and back) on the mast clamps are now ground off at the
>factory.
> 
>Since the mechanism has also been strengthened, this rotator may finally be
>up to the task to rotate large arrays.  However, thanks to comments from
>Frank W3LPL, I do not intend to be the first to find out.  Instead of using
>it to turn the top-of-stack 4el 40 meter Yagi, I think it will do nicely
>turning the top-of-stack 5 el 20 meter Yagi instead.
> 
>Now to look into a prop-pitch and suitable controller...
> 
>73, Keith NM5G
>
>
>  _____  
>
>From: K7LXC at aol.com [mailto:K7LXC at aol.com] 
>Sent: Monday, April 23, 2007 7:05 AM
>To: towertalk at contesting.com; kdutson at sbcglobal.net
>Subject: Re: [TowerTalk] Mast slipping 
>
>
>In a message dated 4/22/2007 7:11:18 P.M. Pacific Daylight Time,
>towertalk-request at contesting.com writes:
>
>>  Frank,
>
>>  Are you saying the Orion has a basic design flaw that no amount of
>strengthening or improvement will correct?  If so, please elaborate.
>
>         Did you miss my recent 4-20 Orion post where I spelled out exactly
>what the design flaws were? Here it is again:
> 
>>      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 per surface 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 which tends to shear them off.
> 
>Cheers,
>Steve   K7LXC
>TOWER TECH  
>
>
>
>
>  _____  
>
>See what's free at AOL.com <http://www.aol.com?ncid=AOLAOF00020000000503> . 
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