In a message dated 98-03-02 07:10:50 EST, you write:
<< I agree that the repairability of Hy-Gain rotators is an important plus.
But I don't think your slam on the Yaesu mast clamps is quite right --
post-1996 production has a fifth bolt for pinning the mast in the clamp, so
that you don't need to tighten it so hard. This *is* a weakness, no doubt,
but not terminal -- by the way, I use a shear pin rather than a bolt, in
the hope that it'll shear before anything major breaks inside the rotator.
Hi, Pete --
When people ask me about pinning masts, my recommendation is that they
don't. I feel that what happens is the forces get pushed down to the next
weak link in the chain. In this case it's a gear or brake. It's much easier
and cheaper to go up occasionally and re-align the antenna than it is to swap
out and repair rotators.
Using a shear pin is fine if you know the shear figure of the pin
corresponding to the forces on the system.
Nonetheless, the Yaesu aluminum clamps WILL break at the slightest
provocation.
> BTW, I notice that Yaesu only rates the G-1000SDX at 2020 ft. lbs of
effective moment. Presuming for a moment that Yaesu and Hy-Gain calculate
this the same way, that means the Ham IV is more powerful than either
Yaesu.
Yes, the Effective Moment is the weight of the antenna multiplied by the
turning radius (I can't remember the Yaesu term for this measurement). This
measurement is an ESTIMATE of the rotator's capacity. It is not the result of
lab testing or anything.
>But would you really use a Ham IV to turn a Tennadyne 10-element LP
and a Cushcraft 40-2CD (not mine, a friend with a G-1000) through three New
England winters? >
If the load was within the capacity of the rotator, why not? I'm a big
believer in over-engineering so personally I would probably use something
bigger. Especially since the rotator is the most common failure in an antenna
system.
>I think that the proper comparison is really with the
T2X, where, again, you can make your fair point about repairability, and
Yaesu can make its points about the control box and weatherproof control
line connectors (standard). >>
Obviously I left out many other details. Yes, there are other pluses and
minuses about these rotators but I was only interested in hitting a couple
high points. It took up a 3-part series in my "Up The Tower" column because
there was so much information. If anyone is interested in a reprint of the
aforementioned series, it's a buck from TOWER TECH, Box 572, Woodinville, WA,
98072.
73, Steve K7LXC
TOWER TECH -- professional tower supplies and services for amateurs
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