Hi Terry:
I have seen exactly what you are describing with TIC rings that do not
completely engage the motor gear with the ring gear for all 360 degrees.
This causes the pot to keep in step - however the antenna does not move in
these "slip" spots. If the antenna comes to rest in one of these slip areas
- more slip can occur (the motor does not engage with the ring).
You will need to have someone turning the antenna from the control box while
someone is properly secured to the tower and can watch the ring gear and
motor as the antenna turns all 360 degrees. There is a bolt on a spring
(model 1032) that allows the pulley to "give" to help keep the motor gear
and the ring gear engaged. This must be properly adjusted for the worst case
gear mesh.
The Green Heron controller can be configured to short the motor terminals
when you are not rotating. Shorting a DC motor causes increased breaking
action. This modification completely solved all motor drift due to wind at
K3LR. Even wind drift was not a problem for calibration as the motor and pot
moved in lock step.
I have been using TIC rings for over 25 years. We have 18 ring rotors in the
air now and more going up next summer. They have their quirks, but by and
large they are very reliable. I have not had a slip calibration issue in
recent memory.
Hope this helps
73,
Tim K3LR
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
Zivney, Terry
Sent: Tuesday, February 18, 2014 2:04 PM
To: towertalk@contesting.com
Subject: [TowerTalk] TIC ring slipping
I have 3 TIC rings on my Rohn 45 tower. THey have been up for 10 or more
years, and give good service. Always turn.
But, I have had a problem from time-to-time with the one holding
the largest antenna - 48 foot boom 5 el 20m and 2 el Cushcraft 40m. The
ring (single motor) seems to turn every time. It holds its position even in
the strongest winds.
BUT, from time to time, generally during a contest, it seems to slip
position. That is, when I start the contest I turn it
SE to use for the Caribbean multipliers. Then next morning,
I turn it NE for Europe to stack with the top 20m beam.
Repeat the second day. When I go out Monday morning
after the contest, I find the antenna, instead of pointing NE,
is pointing roughly East. That is, it has moved somewhere
between 45 and 60 degrees! I can't see the antenna
tower from the shack, and of course, generally the
time I need to turn it is dark, so probably couldn't
see anything anyway.
I can leave the antenna parked there for months, and it
never moves. The antenna NEVER moves (slips) in the other
direction. The TIC ring uses a pot to keep track of direction.
Any ideas?
Terry N4TZ
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