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Side mount rotor limit stops?

To: <towertalk@contesting.com>
Subject: Side mount rotor limit stops?
From: fisher@hp-and2.an.hp.com (Tony Brock-Fisher)
Date: Wed, 3 Jul 1996 09:41:12 -0400
>When you mount a beam on a side mount, do you use some sort of limit switch
>to limit to rotation of the rotor (or rotator, as the case may be) or just
>let the boom crash into the tower leg?

Interesting question. Doug of IIX says to just let the tower limit the
rotation. Jack, W1WEF, tried this approach and had a problem when he
changed to a T2X from a Ham-4. Seems the brake engaged on the T2X and
the rotor jammed and wouldn't budge until he climbed the tower and
took the tension off.

In contemplation of putting up a side mount myself, and in convresations
with Jack, I came up with a solution:

Usually, the dead zone of the sidemount is arranged to conicide with
the rotation stop of the rotator (dead South, usually). If this is
so, the Rotator Pal circuit, described in Feb 1996 QST could be 
modified to provide a zone into which rotation is prevented. Add an
adjustable trim pot on one or either side of R39, the preset pot.
The trim pot(s) should be 250-500 ohms. This will move the ends
of automated rotation away from due south by an adjustable amount.

Never been tried; soon will be; hope this helps...

-Tony, K1KP, fisher@hp-and2.an.hp.com

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