[TowerTalk] Tail Twister Question

[Roger (K8RI) on TT]

On 5/27/2014 8:31 PM, jpk5lad at cox.net wrote:
> Hi Mike --
> The manufacturers of the TX2 (CDE, HyGain, MFJ) always specified it to be operated vertically to maintain that the weight of the mast and antenna array would provide the proper downward thrust on the bearings.
> The only problem I see in a sideways operation is the terrible stress a heavy set of antennas and/or an overly long mast which could provide a fierce moment arm on the body of rotator.  If the rotator was sufficiently down inside the tower and you had a good bushing or bearing on the top to capture most of the array support weight, that might be enough but I'd still be a bit afraid of doing much turning.  It might depend on quite a few factors:  array weight, how far down it's mounted, etc.  An engineer might be able to put some figures to that but it seems like the term, "It depends" figures in a whole lot.

I normally test the Ham series rotators in the vertical position, but 
have done it in the horizontal as well. I'd not put much of a load on 
one in the horizontal as it does not have the proper load on the bearings.

"I would not think", meaning I don't know for sure, that you could 
rotate a fairly large (meaning a hundred # or so) VHF array supported by 
a thrust bearing as a test. As others have said, don't let it get rained 
on in that position.

  73 & good luck,

Roger (K8RI)

>
> If the tower was horizontal enough so that someone else could help support the upper part of the mast while someone turned the TX2 from the shack, I wouldn't think that would place excessive stress on the rotator's body.
>
> I hope this helps.  These notes are not based on any fancy engineering calculations, just my opinion.  It's barely worth twice what you paid for it.
>
> Good luck and 73,
> Jim - K5LAD
>
>
> ---- Mike Fahmie via TowerTalk <towertalk at contesting.com> wrote:
>> Is it safe to operate the TX2 while it is laying on its side ?
>>
>> I don't find anything in the manual EXCEPT for this step in the CHECK OUT section:
>>
>> D. With the rotator sitting in the upright position
>> and connected to the control unit by the 8-
>> wire cable, plug the control unit power cord
>> into a receptacle.
>>
>>
>> That statement raised my caution flags.  The rotor is mounted in the tower and the tower is tilted down to horizontal.  I'd like to run it briefly to check things out before I hand crank it vertical.
>>
>> -Mike-
>> WA6ZTY
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> --
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