[TowerTalk] Does a M2 Orion 2800 fit in a LM354HD top section?

[K4SAV]

I just pulled the info from the web for that calculation which didn't 
mention mast weight.  I went back to the Yaesu manual, and yes that is 
what it says, it includes the mast weight in the calculation.  But that 
really doesn't make sense.  A mast contributes an insignificant amount 
of torque compared to the weight of an antenna, and they are counting 
them the same.  (Antenna turning radius times mast plus antenna weight 
doesn't make a lot of sense to me.)  So obviously the K factor is not a 
guideline for the amount of torque allowed, but must be some kind of 
general really rough swag at trying to sum up the total of what is above 
the rotator.  I'm not sure that is a good way to sum up the requirement. 

Jerry, K4SAV

John Elsik wrote:

>>From the Yaesu manual
>K = turning radius x (antenna + mast weight)
>The mast weighs around 110lbs
>So add 55 lbs to each antenna calculation. Then sum the two
>They give a pretty lengthy example of this in the manual.  Metric of course,
>but the result is the same.
>John
>Wa5zup
>
>-----Original Message-----
>From: towertalk-bounces at contesting.com
>[mailto:towertalk-bounces at contesting.com] On Behalf Of K4SAV
>Sent: Wednesday, March 19, 2008 5:03 PM
>To: towertalk at contesting.com
>Subject: Re: [TowerTalk] Does a M2 Orion 2800 fit in a LM354HD top section?
>
>Are you sure you didn't get a metric number mixed in with the English 
>numbers?  Using Yaesu's method of figuring the K factor, I get 3264 
>ft-lbs for the antennas you have.  The G-2800DXA is rated for 6870 
>ft-lbs.  You are at 47% of the rating.
>
>Jerry, K4SAV
>
>John Elsik wrote:
>
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>>I have a new LM354HDSP crankup tower.  I got the tower up, back in late
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>November.  That is where the project stopped for the winter.  All it is
>holding up is an inv vee for 80 mtrs right now.
>  
>
>>The antennas are a 4el SteppIR and a Cushcraft XM240 on a chrome moly mast.
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>Nothing is installed yet.
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>>I purchased a Yeasu 2800DXA rotor to turn it, but now having second
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>thoughts if the rotor will handle it long term. The "K" factor is 85% of the
>published rotor rating.
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>
>>I called Yeasu and they told me to take the weight off the rotor.  They
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>suggested adding a second plate and bearing between the rotor and tower top
>bearing, and take the weight off.  Sure did not come away with a warm and
>fuzzy feeling that the rotor would handle the load.
>  
>
>>So I am taking pause and sort of rotor shopping.  I realize I would take a
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>hit selling the Yeasu.  I would rather be safe than sorry later.
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>>I was looking at the M2 Orion 2800 (rotor only) and a Green Heron
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>controller.
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>>Will the Orion fit in a LM354HD top section?  I called Tashjian and they
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>could not answer that.
>  
>
>>John
>>wa5zup
>>_______________________________________________
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