[TowerTalk] Re: Shunt feeding tower damages rotor

john at kk9a.com john at kk9a.com
Tue Sep 18 20:01:11 EDT 2007

I own 6 TIC ring rotators and I have never used a capacitor on either the 
potentiometer or the motor.  The only problem that I have had with either 
component was due to lightning strikes, however I never shunt fed my towers. 
I'm not sure what the purpose of the capacitor is.

John KK9A

To: towertalk at contesting.com
Subject: [TowerTalk] Shunt feeding tower damages rotor
From: Paul Baldock
Date: Tue, 18 Sep 2007 13:39:33 -0700
List-post: <mailto:towertalk at contesting.com>

I have an M2 rotor at the top of my 130ft Tower fed with shielded
cable, and a TIC ring at 92ft fed with non-shielded cable. I shunt
feed the tower for 160M. All as has gone well for a couple of years.

I just changed the top antenna (much more capacitance) and had to
re-tune the tower shunt feed. This of course changes the
voltage/current distribution in the tower.

Having put 1.5KW in to the tower it seems that I damaged the TIC
Ring. At the tower the TIC ring consists of a floating motor with
.1uF to ground (the tower). The feed back pot is also floating with
.01uFcaps to ground (the tower). From measurements on the ground it
appears that  I have damaged one or both of the Pot Caps to ground to
cause them to be leaky.

The question is, should I just remove the Pot Caps, or replace them
with beefier caps, or stop shunt feeding the tower.


- Paul  KW7Y 

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