[ADXA] rotator mast pinning

[J. Setcer]

[image: IMG_1030.JPG]
Dennis,   Do you mean THAT antenna? I hated & hated that antenna!
I never did figure out if we even had the elements in the right order.
Different owner's Manuals had different configs.

But NO. The Mast was not Pinned, just Good & tight. I trusted the rotor
enough to stand on it.
- QJ
---

On Sat, Sep 7, 2024 at 6:55 PM Dennis Schaefer <dennisw5rz at gmail.com> wrote:

> After my comment about pinning the mast, I thought I should research the
> issue again since I’m getting ready to swap out a rotator.   I have to say
> right up front that in the last 35 years or so, I have never gone up the
> tower to correct an aiming error.   With rotator repairs and several
> antenna change-outs during that time, making  sure the mast clamps were
> properly tightened every few years did the job.
>
> I read lots of comments, many in the old tower talk forum, where the big
> dogs hung out.  The word most often associated with NOT pinning the mast
> was “nuisance” or “inconvenience”.  The words most often associated with
> pinning the mast was “catastrophic failure”.    A reason often given for
> pinning the mast was “Yaesu said to do it”.
>
> I understand that catastrophic failure caused by pinning  is rare and
> unlikely, but brake wedge failure and bell housing damage were often
> mentioned.  This would probably only occur with a very large and/or
> unbalanced antenna.   The problem is that big antennas  exert more torque
> and are more likely to cause slippage.  Pinning the mast might be
>  necessary for those really big antennas.  You’re going to spend time and
> money maintaining a large antenna system anyway.
>
> My antennas have usually been relatively small tribanders, except for the
> Mosley PRO-57, which was a little larger.  My C-3 has been trouble free and
> slippage free for over 20 years and I don’t expect any problems.  If I had
> a 30 foot boom, I would anticipate problems, such as more rotator failure,
> weather damage, sheared mast pin bolts, etc.  That’s one reason I stick
> with smaller antennas.
>
> This article seems sensible:
> https://ve3vn.blogspot.com/2022/02/hy-gain-rotator-mast-slippage.html
>
> I just remembered something - At our club station, we had a KLM KT-34XA,
> which was a pretty big tribander.  (about a 36 foot boom and very
> unbalanced).  We found a bunch of ball bearings on the ground from its
> Ham-4 after some wind.  I don’t remember if the mast was pinned, or just
> good and tight, but it did not slip, and there was catastrophic damage to
> the rotator.  Would it have helped if the mast had slipped?  Maybe, maybe
> not.
>
> I’m not trying to change anyone’s mind, or soliciting comments or
> arguments - it’s like politics, everyone has their minds made up.  By all
> means, do what you are comfortable with.   I just did this research to
> refresh my knowledge and wanted to share my thoughts.   I learn a lot from
> ADXA members and seldom have anything technical to contribute.
>
> 73,
> Dennis/RZ
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