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Re: [TowerTalk] Rotor Selection Advice Wanted - Heavy Duty

Subject: Re: [TowerTalk] Rotor Selection Advice Wanted - Heavy Duty
From: <>
Date: Tue, 9 Jan 2007 00:13:41 -0500 (EST)
List-post: <>

I installed two M2 Orion 2800s in 1998, they've very reliably turned
a 48 foot boom 15M Yagi on a 200 foot tower, and a 48 foot boom 20M
Yagi on another 200 foot tower.  Both of these rotators take a serious
beating in the wind with no difficulty at all, and there's no reason to
baby sit them by pointing the antennas into the wind etc.

I use a "small" prop-pitch on another 200 foot tower.  It easily turns a
full size 3 element 48 foot boom Yagi.  The wind load of this large
antenna is slightly larger than the wind load of a MonstIR.  I wouldn't
even consider trying to turn this antenna with a M2 Orion 2800, it
produces far too much wind load for a mid-sized rotator.

The initial symptom of an undersized rotator is boom slippage in
moderate winds.  Redesigning the manufacturer's mounting clamps will reduce or 
eliminate the slippage, but result in destruction of the
rotator in high winds.

None of the above suggests that there's a problem with the M2 Orion.
I own four M2 Orion 2800s, and I'd purchase more in a flash when I need
them. Its an exceptionally reliable rotator for all but the very
largest antennas, for which it was never intended.
The MonstIR is in this class of very large antennas that requires a
large rotator, such as a small prop-pitch, or -- based on favorable
reports here -- a large rotator such as the Prosistel 67 or the
Yaesu 2800.

On a related note, the 2 inch mast commonly used with MonstIR installations 
presents a serious mast slippage problem for almost any
clamping system.  If you can substitute a 3 inch mast, you'll have a
much improved installation.


---- Original message ----
>Date: Mon, 8 Jan 2007 16:36:36 -0800 (PST)
>From: "Rick Karlquist" <>  
>Subject: Re: [TowerTalk] Rotor Selection Advice Wanted - Heavy Duty  
> wrote:
>> I should have been clearer in my reply to Rick's e-mail.  Rick discussed
>> using an M2 Orion 2800 or a prop-pitch rotator with the MonstIR.
>> The M2 2800 Orion rotator has insufficient capacity to hold the MonstIR in
>> a moderate wind, while a prop-pitch will handle the MonstIR easily under
>> any conditions that the MonstIR can survive.
>> I did not intend to make a comment regarding the Yaesu G2800DXA, and I'm
>> sorry my e-mail wasn't specific enough to avoid unintentionally
>> interpreting it that way.
>> 73!
>> Frank
>> W3LPL
>That's really helpful, Frank.  I had no idea how inadequate the Orion
>was.  On K7NV's web site, he talks about "small, medium, and large"
>prop-pitch units.  Is the "small" one adequate for the MonstIR?  I am
>not sure if the "medium" one can fit into my 15" top tower section.
>Rick N6RK

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