[TowerTalk] Experience with M2 Orion 3800 Rotator and Rohn TB-4 Thrust Bearnings

[Robert Harmon]

Tom,

Thanks for your information on using the 2800.   I am very interested in the comments from this thread, I have a new 2800 I will be installing soon.
The weatherboot is something I am planning to do over the Orion top section.  I will check out the vent pipe pieces available.  


73,
Bob
K6UJ



> On Jul 18, 2015, at 6:22 AM, Tom_N2SR via TowerTalk <towertalk at contesting.com> wrote:
> 
> I am using an M2 Orion 2800 to turn a Force 12 240N Magnum, which is 10 feet above the top of the tower, on a2" chrome molly mast.  There was also a TH7 at the top of the tower, which I have taken down.  The future plan isto put up a homebrew 3 element 30M beam at the top of the tower.   
> 
> On a few opinions, I did not use the Orion mast clamp.  I opted to go with K7NV's clamp.  Kurt's clamp holds so 
> well, that when I was aligning the rotator direction and the antenna, I had ONE bolt in the clamp finger tight and 
> could not turn the mast.   
> 
> I use standard rotator cable.  Never had an issue with intermittent pulse counts.  That could be because I only havea ~ 150 run to the shack.  
> 
> I was also going to use two thrust bearings, but on a few opinions, I only have one at the top of the tower.  Nearthe rotator, I have a bearing plate, where if necessary, I can raise the mast and clamp it in place.   
> 
> If you decide to use two bearings, they have to be perfectly aligned, or the assembly will bind.  
> 
> Some have mentioned water egress into the top of the rotator.   I've never seen that, but if you decide to use a weatherboot for that, the local home centers have a "generic vent pipe" piece.  It's got a bunch of "step" sizes for different sizevent pipe.  I put one over my bearing at the top of the tower.  
> 
> Never have had any issues with the setup.  
> 
> Tom, N2SR
>     From: Jack Ference <jackference at gmail.com>
> To: towertalk at contesting.com 
> Sent: Friday, July 17, 2015 8:15 PM
> Subject: [TowerTalk] Experience with M2 Orion 3800 Rotator and Rohn TB-4 Thrust Bearnings
> 
> Hi,
> 
> I am planning a tower installation using 85 ft of AB-105  guyed at 35 ft
> and 75 ft supporting a 4 el Steppir (32 ft boom and approx. 10 sq ft wind
> load) at about a foot above the top of the tower and a Cushcraft XM-240 or
> JK Antennas 3040 (boom length in range of 18 ft and wind load between 5.5
> and 9 sq ft.) about 12 ft above the lower antenna. A 22 ft, 3" chrome-moly
> mast with a 3/16" or 1/4" wall will be used to support the antennas.
> 
> I am planning on using an M2 Orion 2800 mounted on a shelf about 5-6 ft
> below the top of the tower and two TB-4 thrust bearings, one at the top of
> the tower and one 3 ft down.
> 
> If anyone has experience using the M2 Orion 2800 Rotator and TB-4 thrust
> bearings and antennas with a total wind load in the range of 15-18 sq ft, I
> would appreciate hearing from you via the reflector.
> 
> Thanks in advance,
> 
> -- 
> *Jack J. Ference, W3KX*
> jackference at gmail.com
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