I've been using a TIC ring rotator here on a big 7el 10m Yagi for the
past 20 years with good success, but it has a couple of well-known
unresolved problems: In the high winds we have on our hilltop (147 mi/h
3s gust measured), it can jump a tooth on the motor or pot gear, which
eventually makes the direction indicator pot totally out of sync, or
even damages it. Since the ring rotor doesn't have physical limit
switches, that has permitted over-rotation that parts the coax.
Re direction indication, has anyone had any success with alternatives
such as magnetic or microswitch gear tooth counters? Or a simple compass
module with output that a Green Heron RT-21 can read (0-5 volts)? See
G6EJD, KJ4JJH, K3NG. I'd like to have direction indication that mounts
directly at the ring or antenna boom itself, rather than through a
coupled gear. and it should work at zero speed.
Second, has anyone had success with adding waterproof (IP67) limit
switches? Honeywell, Omron, IP67 microswitches or cheaper imports? If a
magnetic gear tooth sensor is used, what kind of spacing precision is
required? With 360 teeth, the 1° precision should be plenty for HF.
I am aware of modifications and updates (e.g., N1CX) that may help
prevent gear tooth skipping, but I want something bullet-proof that
really gives me full confidence. Even a partial failure in a contest can
compromise an otherwise winning effort; in our big HC8 station, we gave
up on rotators and went with multiple antennas per band. But for my less
complex setup here at home, I intend to try to resolve both of these
problems when the weather permits, and am interested in hearing the
experiences of list folks.
BTW, I resolved the climb-over issue with a small 3-rung steel ladder
mounted below it on the tower face. And if the limit switches work out,
I'll add them to my prop pitches, as well.
Thanks, Dave W6NL/HC8L
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