[Towertalk] Prop-Pitch

[N9EN@VOYAGER.NET]

Hello all;

For those needing a super-accurate direction indication
system for a prop-pitch motor (or any other kind of a
motor that they're using to turn an antenna system) I have
for sale a number of units that will do the job very nicely.

I installed one of these in my OLD HyGain commercial
RBX-5 rotator when I found out that the WWII surplus
400 cycle selsyn motors (with which the HyGain RBX-5
was originally equipped) wouldn't stay in calibration, due
to the fact that my rotator was 250' from my control box.

The unit that I am using is a NAMCO brand programmable
limit switch that has been set for position indication. I set
it to indicate a span from 0 to 359 (the degrees of the com-
pass) and it has a 3-digit red LED digital read-out that
indicates the degrees of the compass where my antenna
is aimed. The unit is VERY precise.

These NAMCO units were manufactured by one of the
more well-known companies that makes proximity
switches, photoeyes, etc. for industrial applications. The
NAMCO programmable limit switch system uses a small
resolver motor that is connected to the "control box" with
3-pair shielded cable. The factory recommends that cable
with individually-shielded pairs be used to keep the unit
from being affected by noise but I have used regular 3-pair
shielded cable with them and they work just fine with that.
I think the reason why the company recommends the 3-pair
individually shielded cable to be used is because normally,
these units are installed in an industrial environment where
there is a lot of electrical noise present.

Anyway, I have a number of these units for sale at $150
each. I was able to obtain them from a factory where I
had previously worked. They had been originally installed
on ABB robotic welding systems that travelled on a
gantry and were used to indicate the "7th axis position"
of the robot (the position along the gantry).

If anyone is interested in a very precise direction indication
system and would like to contact me in regards to pur-
chasing one of these, feel free to do so.

73 de Brad, N9EN @ Radio Free Roscoe (IL)...
----- Original Message -----
From: "Greg Gobleman" <k9zm@frontiernet.net>
To: "TowerTalk" <TowerTalk@contesting.com>
Sent: Saturday, June 01, 2002 10:24 PM
Subject: Re: [Towertalk] Prop-Pitch


> I was looking at the photos of this prop pitch, not having seen one mounted
> I was trying to figure out how they are installed.  I assume the flat plate
> area is bolted to a stationary plate.  Is a notched piece made to adapt to
> the mast pipe?  I also have read of needing to rig a directional indicator
> of some kind.  Any info on that?  May I assume that the control box and
> indicator will probably cost as much as the rotor?
>
> 73
> Greg K9ZM
>
>
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