For a wood telephone pole mounted A4S I built a similar, but longer,
cage ala W8WWV. I made it about 3.5' long from rotator shelf to thrust
bearing as to reduce the moment on the rotator (the antenna is on 4' of
mast is above the thrust bearing) and to permit hoisting the mast for
rotator maintenance. It is welded up from 1.5" x 1/8" angle HRS. Since
the Yaesu (and Rohn) thrust bearings have little or no angular
resistance/strength, I have a bolt on mast restrainer made from some 2"
angle steel so the weight is taken by it with the rotator out and so the
mast can not tilt when it is hoisted. The UST towers use a thrust tube
(no bearings) so the mast is tilt constrained when hoisted free of the
rotator. That is another option for cage design.
Grant KZ1W
On 6/15/2012 8:13 AM, Michael Tope wrote:
> I think the cage pictured on the G0HWC website is the same cage sold in
> the U.K. by Tennamast
>
> http://stores.ebay.com/Tennamast?_trksid=p4340.l2563
>
> Also, Greg Ordy W8WWV has a homebrew cage on his website:
>
> http://www.seed-solutions.com/gregordy/Amateur%20Radio/Experimentation/RotatorCage.htm
>
> 73, Mike W4EF..............
>
>
>
> On 6/14/2012 4:52 AM, john@kk9a.com wrote:
>> I agree with Kurt, adding a bearing plate is the best approach for your
>> tower. Here is one example: http://www.g0hwc.com/latest_projects.html
>>
>> GL,
>> John KK9A
>>
>>
>> from [Rick Kiessig] [Permanent Link][Original]
>> To: <towertalk@contesting.com>
>> Subject: [TowerTalk] Rotator cage design
>> Date: Thu, 14 Jun 2012 18:02:12 +1200
>>
>>
>> I understand that rotators are not designed to handle lateral loads, and
>> that I should therefore have the rotator on one shelf, then a second shelf
>> above that with a radial support bearing on it, to handle the lateral
>> loads. The most likely antenna at the moment (still a moving target)
>> weighs 29kg, with a 7.2 sq ft wind load and a 6m turning radius. Kurt K7NV
>> suggested welding two plates on the side of my pole/tower, at the top, a
>> few feet apart. Does anyone know of existing designs/drawings for that
>> kind of
>> thing?
>>
>> 73, Rick ZL2HAM
>
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>
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