[amsat-bb] AMSAT-BB Digest, Vol 14, Issue 368

[John Kopala]

   Re: Counterbalance weight on antenna rotator? (Bob Hammond)

My antennas are mostly "center" mounted because of their length and are
pretty well balanced as a result.  For antennas rear mounted to the cross
boom, a length of tubing extending in the opposite direction from the
antennas could be used with an adjustable weight that can be positioned to
achieve the correct balance.  The idea of a counter balance weight is
interesting, but the antennas present a variable load depending upon the
elevation.  The weight on the cable presents a constant load independent of
the elevation.  Worse yet, I use a flip mode tracking that resolves the
issue of having the satellite path cross the stops of the azimuth rotor and
having to rotate the antennas 360 degrees to continue tracking the
satellite.  But this requires 180 degree movement of the elevation rotor.
The weight on a cable would then add to the weight of the antennas which
would make the problem worse and make the elevation rotor work twice as
hard.  See a picture of my home satellite installation on qrz.com by
looking up N7JK.  Using an opposing counterbalance weight mounted opposite
the antennas can essentially change the function of the elevation rotor to
being simply a positioning device if the array is properly balanced.
John Kopala
N7JK
----------------------------------------------------------------------

Message: 1
Date: Sat, 5 Oct 2019 10:28:21 -0700
From: Bob Hammond <propgrinder at gmail.com>
To: amsat-bb at amsat.org
Subject: Re: [amsat-bb] Counterbalance weight on antenna rotator?
Message-ID:
        <CAKoB7OraohpJPFc1rQdu5_mxsY7jzAQAS7BBn7MJwjrkvR23VQ at mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"

What do all think of this idea?  Pictured is a trial weight (20 lbs).  I
envision using stainless steel cable instead of the nylon rope for security
and safety.  As the antenna crossboom is rotated, the rope unwinds.

Bob
W7OTJ
:56 AM Bob Hammond <propgrinder at gmail.com> wrote:

> Do a lot of you, or all, use a counterbalance weight on your elevation
> rotor?  If so, how did you implement it?
>
> I have 3 antennas (2M, 70cm, 23cm) on my cross boom and want to reduce the
> load on the Yaesu rotor so it lasts longer.
>
> 73s,
>
> Bob
> W7OTJ
>