Paul Kelley N1BUG wrote:
> OK, I know this has got to be a dumb question, but here goes.
>
> Most of my ham career I never used real antenna rotators. I used
> homebrew contraptions or the like. Now I have an 80 foot tower with
> a rebuilt and "upgraded" Ham M rotor (yes I'm aware of the
> controversy regarding the "upgrade" in question) and a 100 foot
> tower with a Ham IV.
>
> The Ham IV works fine in all seasons and weather conditions, never a
> problem. The Ham M, however, is useless much of the winter. Snow
> melts off antennas above, water drips down and forms a thin layer of
> ice on the rotor shelf. The ice is just thick enough to seize the
> lower rotating part of the bell housing so the rotor can't turn.
Are you sure this is what's happening? Have you actually seen this
layer of ice?
I ask as I've never seen it happen, but I have seen condensation inside
the rotator freeze. The motor in the Ham series has very little torque
and depends on the gearing to turn that into enough to handle a good
size tribander. It takes very little inside the rotator to keep it from
turning.
If it really is a layer build up on the shelf, then I'd simply put some
washers over the bolts to serve as spacers to raise the rotator about a
1/8th to 1/4" above the shelf which is not necessarily all that easy.
73 and good luck,
Roger (K8RI)
> I
> have climbed up there several times (in past winters) to verify that
> is the problem. If I chip away or melt the ice all is well until the
> next thaw/freeze or rain/freeze event.
>
> I have a few questions about this.
>
> 1.) Why is this happening to the Ham M and not the Ham IV? Is there
> a physical difference in these two rotors that explains it? (I am
> currently unable to climb to inspect this -- a temporary situation,
> hopefully)
>
> 2.) How can I stop this from happening? Is it advisable to put
> spacers between the Ham M rotor base and the rotor shelf to provide
> more clearance for the rotating portion of the rotor? If so, any
> recommendations or potential pitfalls to avoid? Are there other
> possible solutions for this problem?
>
> 3.) I don't recall ever hearing anyone mention a similar issue.
> Maybe I just wasn't paying attention, but, could there be something
> wrong with my "upgraded" Ham M that is causing this? I can't see how
> it could be assembled wrong and still work fine, aside from the
> icing, but...?
>
> Thanks in advance for any education and/or suggestions in this
> matter! In the previous couple of winters it was up there, this was
> a minor annoyance. If it was frozen and I wanted to turn it, I just
> climbed up and removed the ice. Now that I can't do that, it's
> driving me crazy! (er... more crazy? ;-)
>
> 73,
> Paul N1BUG
>
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