[TowerTalk] Prop pitch question

john at kk9a.com john at kk9a.com
Fri May 22 20:18:29 EDT 2020


I would be surprised if your prop pitch is free wheeling unless the MonstIR
is out of balance. K7NV may be the only rotator manufacture to figure out
that there is more clamping surface area when using a round clamp on a round
mast! I doubt that his clamp is slipping. I use DX Engineering 3" saddle
clamps on my antennas.  I have never had the antennas slip on the mast -
what does SteppIR use?  

John KK9A

Richard (Rick) N6RK wrote:

I have a MonstIR turned by a K7NV "small" prop pitch.  I don't
know how big your Yagi is, but mine has full size elements
(70 feet long) on a 36 foot boom.

I have been having the beam turn a bit during high winds.
It never occurred to me that the prop pitch could be free
wheeling.  I assumed it was either the mast slipping in
the prop pitch clamp or the boom slipping on the mast.
The K7NV has probably the best mast clamp ever made.
Also I have a Slipp-Nott on the boom to mast plate.
Now that I think about it, the free wheeling theory
makes some sense.

This raises the question:  how did you determine that
the slipping was due to the rotor gears, as opposed
to the rotor to mast clamp or the mast to boom plate?
Thinking out loud here (a bad habit of mine), should
I leave the rotor control box turned on all the time,
especially on windy days, with the rotor parked at zero
degrees azimuth.  AFAIK, the display on the box will
indicate any free wheeling of the prop pitch, but will
do nothing if the mast is slipping.  So far, I usually
turn it off when not on the air (or during a 160 meter
contest, hi) and I am assuming it is completely off
and wouldn't record free wheeling.  The box is a legacy
Green Heron (still works great after 15 years).

73
Rick N6RK



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