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

[Tom_N2SR]

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
_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk at contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk