[TowerTalk] Ring Rotors

Mon Jan 30 20:09:13 EST 2023

Since downloads aren't available for NCJ, is anybody able to provide a 
different link/download?

Grant KZ1W

On 1/30/2023 15:14, Chuck R. Korzendorfer wrote:
> W9RE has a very nice design for his rotating side mount in the Sept/Oct., 1987 issue of NCJ using structural aluminum plate & angle.  I am in the middle of building one for a small tribander.
> KM5G
> 
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> ________________________________
> From: TowerTalk <towertalk-bounces at contesting.com> on behalf of Grant Saviers <grants2 at pacbell.net>
> Sent: Monday, January 30, 2023 5:08:15 PM
> To: towertalk at contesting.com <towertalk at contesting.com>
> Subject: Re: [TowerTalk] Ring Rotors
> 
> [External Email]
> 
> Might be better as a new topic "swing arm mounts"
> 
> Some expert advice I got was to use crossed A36 angle steel (2x2x1/4 or
> 1.5x1.5x3/16) U-bolted to all three legs and mount the rotator close to
> the tower on a 3/16 plate bolted in the V in the outside gap.
> 
> Repeat for the top bearing, xx feet above the rotator.  Could use a
> stock "thrust" bearing or a simple UHMW block with all the load on the
> rotator.
> 
> The swing arms were about 33" long mounted the the mast, which was going
> to be 1-7/8" x 0.188" 1026 DOM.  The mast was to be 13ft between mounts
> so able to mount 2 yagis.  A triangular brace mast to arm and a stub
> mast welded on the arm to mount the antenna with a stock mast-boom
> clamp.  Of course YMMV.
> 
> It's important to have all three legs capture the loading.
> 
> Ideally get it all hot dip galvanized or do a good pant job.
> 
> And find a PE to recommend a design for the planned yagis.
> 
> Grant KZ1W
> 
> On 1/30/2023 11:32, Steve Maki wrote:
>> On 1/30/2023 2:23 PM, Lux, Jim wrote:
>>
>>> On 1/30/23 11:10 AM, Steve Maki wrote:
>>>> On 1/30/2023 1:48 PM, Lux, Jim wrote:
>>>>
>>>>> On 1/30/23 9:46 AM, Grant Saviers wrote:
>>>>>> I agree side mount + swing arm is a good option.
>>>>>>
>>>>>> Although my 7 K0XG R65 rings have worked great minus one motor
>>>>>> failure, I would do side mounts for future (unlikely) towers.
>>>>>>
>>>>>> The advantages of side mounts are lower cost & weight, using
>>>>>> standard rotators, and if desired with multiple beams on a long
>>>>>> mast between rotator and top support.
>>>>>>
>>>>>> The side mount disadvantages are less rotation (but still can get
>>>>>> ~250*), some offset load on the tower (use 6 guys or star
>>>>>> brackets), and easily fabricated or purchased unique parts,
>>>>>> although you/PE need a design.
>>>>>>
>>>>>> I think the updated Orion 2800 is a better choice than the Yaesu
>>>>>> for very big beams.
>>>>
>>>>> I've been thinking about this, and I wonder if there were some "not
>>>>> too complex" scheme with an extra hinge point on the arm that would
>>>>> get you 360 degrees.  Not that I would build such a thing (would
>>>>> that I had room for it) - but I was thinking if you had an arm that
>>>>> is the length of a "face" of the tower, and some sort of offset
>>>>> crank linkage, you could get 360 of rotation from 240 degrees (or
>>>>> less) of movement from the primary arm.   My mind's eye has this as
>>>>> like a "wrist" that reaches around the tower. Yeah, you'd have the
>>>>> mass of the antenna as a cantilever load, which would put a bending
>>>>> moment on the tower.
>>>>
>>>> A swing arm where the rotor is mounted straight off a tower leg is
>>>> good for 300° easy. That's plenty as long as you have another antenna
>>>> to cover the dead zone.
>>>
>>> Oh yeah, I figured that.. I was just contemplating "clever mechanical
>>> solutions" - The swing arm is actually a nice solution in general -
>>> simple, uses off the shelf stuff, can be added after the tower is up,
>>> etc.
>>>
>>> It's like the hinge plates for mounting an antenna on a tower/mast
>>> that pivots from horizontal to vertical - a simple clever solution.
>>>
>>> Of course, the other solution is to mount two (or three) Yagis and a
>>> combining network to phase them (or just switch). <grin>
>>
>> Yep, I was trying to picture your idea. Back when linear actuators were
>> cheap (used in the satellite dish industry) I put some time into
>> thinking about a way to use one or two to turn a large yagi on a swing
>> gate. It never got past day dreaming and a little pencil scratching.
>>
>> -Steve K8LX
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