I have a Yaesu G-1000 rotor mounted on the top of a 60' Aluma crank-up tower,
no thrust bearing. Right above the rotor is a KLM KT-34XA on a 6' 2" dia
aluminum mast. On the top of that is a 3 el 6M Yagi. Going on 20 years with no
issues. Highest recorded gust was 70 MPH, tower was cranked up! When I saw 85
MPH at work, I came home and lowered the tower. It was swaying in the wind.
Pix on request.
---
Ciao baby, catch you on the flip side
73 de W3AB/GEOAFA9GB
WA2LSI, KE6RJW, W6B, W7B, AAR9AG
http://www.w3ab.org
Don't be a worrier, be a warrior.
On Tuesday, July 18, 2023 at 09:01:19 AM PDT,
<towertalk-request@contesting.com> wrote:
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Today's Topics:
1. Thrust bearing for AB-577?? (Pete Smith N4ZR)
2. Re: Thrust bearing for AB-577?? (Joe Subich, W4TV)
3. Re: Thrust bearing for AB-577?? (Pete Smith N4ZR)
----------------------------------------------------------------------
Message: 1
Date: Tue, 18 Jul 2023 09:41:47 -0400
From: Pete Smith N4ZR <pete.n4zr@gmail.com>
To: TowerTalk <TowerTalk@contesting.com>
Subject: [TowerTalk] Thrust bearing for AB-577??
Message-ID: <fa20f70c-17f1-5c68-7c53-878ed7f8b0fc@gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
I have a C-3E tribander on an AB-577 "rocket launcher."? I also have a
3-element 6-meter yagi that I was planning to mount 6 feet above the
Yaesu rotator at the top of the 577, but was deterred by concern of some
knowledgeable hams that this might overload the rotator and cause a
catastrophic failure, destroying the rotator and the tribander.? That's
just too big a risk for me.
It occurs to me to wonder whether someone out there has contrived a way
to mount a thrust bearing above the rotator on an AB-577?? I can
visualize what this might look like, involving a structure attached to
the top of the top-most tube below the rotator and supporting a thrust
bearing a foot or so above, but don't want to reinvent the wheel unless
necessary.
--
73, Pete N4ZR
------------------------------
Message: 2
Date: Tue, 18 Jul 2023 11:05:40 -0400
From: "Joe Subich, W4TV" <lists@subich.com>
To: Pete Smith N4ZR <pete.n4zr@gmail.com>, "[TowerTalk]"
<towertalk@contesting.com>
Subject: Re: [TowerTalk] Thrust bearing for AB-577??
Message-ID: <1743084c-ba50-512f-6789-f3b363578b0b@subich.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Yaesu show a mast bearing - mount to the mast above the rotator and
guy - but with your relatively small load I don't see a need for it.
Look at the loads K7NV had on his AB-577(s) with no bearing above the
rotator. His TH7 represents significantly more load that you are
proposing.
73,
... Joe, W4TV
On 7/18/2023 9:41 AM, Pete Smith N4ZR wrote:
> I have a C-3E tribander on an AB-577 "rocket launcher."? I also have a
> 3-element 6-meter yagi that I was planning to mount 6 feet above the
> Yaesu rotator at the top of the 577, but was deterred by concern of some
> knowledgeable hams that this might overload the rotator and cause a
> catastrophic failure, destroying the rotator and the tribander.? That's
> just too big a risk for me.
>
> It occurs to me to wonder whether someone out there has contrived a way
> to mount a thrust bearing above the rotator on an AB-577?? I can
> visualize what this might look like, involving a structure attached to
> the top of the top-most tube below the rotator and supporting a thrust
> bearing a foot or so above, but don't want to reinvent the wheel unless
> necessary.
>
------------------------------
Message: 3
Date: Tue, 18 Jul 2023 11:37:18 -0400
From: Pete Smith N4ZR <pete.n4zr@gmail.com>
To: "Joe Subich, W4TV" <lists@subich.com>, "[TowerTalk]"
<towertalk@contesting.com>
Subject: Re: [TowerTalk] Thrust bearing for AB-577??
Message-ID: <c6d61828-1ece-f882-f82a-e3bd845fdeb4@gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
That's true, Joe - the thing that concerned people was the 6-foot lever
arm above the tri-bander, even though the antenna mounted at the top of
it is quite small.
73, Pete N4ZR
On 7/18/2023 11:05 AM, Joe Subich, W4TV wrote:
>
> Yaesu show a mast bearing - mount to the mast above the rotator and
> guy - but with your relatively small load I don't see a need for it.
>
> Look at the loads K7NV had on his AB-577(s) with no bearing above the
> rotator.? His TH7 represents significantly more load that you are
> proposing.
>
> 73,
>
> ?? ... Joe, W4TV
>
> On 7/18/2023 9:41 AM, Pete Smith N4ZR wrote:
>> I have a C-3E tribander on an AB-577 "rocket launcher."? I also have
>> a 3-element 6-meter yagi that I was planning to mount 6 feet above
>> the Yaesu rotator at the top of the 577, but was deterred by concern
>> of some knowledgeable hams that this might overload the rotator and
>> cause a catastrophic failure, destroying the rotator and the
>> tribander. That's just too big a risk for me.
>>
>> It occurs to me to wonder whether someone out there has contrived a
>> way to mount a thrust bearing above the rotator on an AB-577?? I can
>> visualize what this might look like, involving a structure attached
>> to the top of the top-most tube below the rotator and supporting a
>> thrust bearing a foot or so above, but don't want to reinvent the
>> wheel unless necessary.
>>
------------------------------
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