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Re: counter wieght queistion



A counterweight is used to balance a dish or antenna assembly when the
center of gravity is substantially either forward or behind the center or
rotation of the elevation rotor. For example,  a 1.2 meter dish which weighs
50 lbs might have its center of gravity when the dish is pointing to the
horizon say 9 inches from the center of rotation of the elevation mast would
produce 9/12 * 50# = 37.5 ft lbs of torque which the rotor would have to
overcome to raise the dish. This puts a substantial load on the rotor,
causing premature failure or the necessity of buying a heavier duty (read
expensive) model.

With our example of the 1.2 meter dish, mounting a 19 lb weight on an arm
extending 2 feet out on the opposite side of the axis of rotation as the
dish would nearly perfectly counterbalance the dish. What it means in
practical terms is that you might get away with using that old surplus
Alliance TV rotor, rather than having to go out and buy that $600 Yaesu
G5600 setup. Of  course the counterweight will not help you with windload,
but it eliminates a major source of strain on your pointing system.
----- Original Message -----
From: John Becker <molou@big-river.net>
To: <amsat-bb@AMSAT.Org>
Sent: Friday, June 28, 2002 6:51 PM
Subject: [amsat-bb] counter wieght queistion


> When does one need to use such a thing?
>
>
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>

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