[TowerTalk] Ham IV Rotor Problem

[Robert Shohet]

Hi Jim,

It sounds like the rotor is binding IN the tower.  Something is preventing
it from rotating properly through 360 degrees.

Possibilities include:

1) The antenna/rotor assembly is unbalanced for weight and at the direction
of stopping, overloads the rotators ability to turn
2) Something is binding against rotator assembly IN THE TOWER - maybe a shim
is needed or there is a piece of metal sticking out and catching on
something
3) There is an issue with the control box (unlikely)
4) The rotor is misaligned for direction - maybe it stops turning at the
stop and the control box does not show that properly.
5) The Thrust bearing is too tight and it will bind in only one spot!
6) Something simple and easy to overlook

I have had rotators stop turning in the past for reasons 1-4.  On one
occasion, the rotator turned fine when it rained and would bind only in dry
wx.  I was due to a tight TB-3 thrust bearing and would bind, just barely,
in one spot in DRY wx only.
When it was dry and WINDY, it did not bind.  When it was wet it did not
bind.  I finally figured it out and loosened the TB3 just a tiny bit.  No
more binding.

Let us know what you find.  GL!

73
Bob KQ2M

----- Original Message -----
From: "Jim Brown" <jbrown at luminet.net>
To: <towertalk at contesting.com>
Sent: Monday, December 01, 2003 3:13 PM
Subject: [TowerTalk] Ham IV Rotor Problem


I searched the archives for this problem but the remedy given doesn't
help in my situation. Here's the problem. When my rotor is pointed to
the west / southwest and stopped there it doesn't want to restart. The
first thing I did was to make sure the coax was not binding, and then I
loosened the mast clamp and tried the rotator with no load and still had
the problem. I took it down from the tower yesterday and tried it
plugged directly plugged into the control box. Everything worked fine.
As per suggestions on the reflector I installed new rotor cable and
reinstalled the rotor. The problem was back. So what I know is that it
is not binding, coax is not interfering and there is new rotor cable.
Any other suggestions other than sending it to CATS. I am concerned that
it will bench test OK for them. Thanks fin advance for the help.

Jim NØWE
jbrown at luminet.net