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Loop rotor

 

I just saw this RCA rotor on sale, I don't know that is is precise enough, because it is programmable for every 10 degrees. I haven't read the manual
far enough to see if you can precisely set direction to null your noise sources or if you can fool it to ever 5degrees by only turning 180 degrees.
It is $89 on sale with rebate.? $14 shipping, at least to me in Fl.
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Here's the manual,
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I have the predecessor unit and it is just a two winding capacitor (direction) induction motor with a gear train. The digital display seems to be counting AC cycles. A strong wind (or in my case power mains failure) can push a 12' yagi out of alignment. In short it is not like a CDR type with an internal wire wound resistor measuring direction.

Sort of a shame the WW2 400 Hz selsyns are no longer "inexpensive" although a PM magnet, an Arduino flux compass, and some hot glue will probably replace a selsyn and all the analog hardware to remotely read out azimuth position in degrees.
 

There is a re-calibration sequence in the manual if it get out of whack, but I'm not sure if it covers that situation.
 

I have that exact rotator. It is fine for a 1 to 1.5m diameter loop. Although the readout only indicates 10 degree steps, it can be "jogged" to any position allowing good nulls if necessary. Tom
 

On Sun, Feb 23, 2025 at 10:01 PM, James Redding WA9VEZ wrote:
Sort of a shame the WW2 400 Hz selsyns are no longer "inexpensive" although a PM magnet, an Arduino flux compass, and some hot glue will probably replace a selsyn and all the analog hardware to remotely read out azimuth position in degrees.
I've agonised over azimuth sensing - been looking for a battery-powered device with built-in Wi-Fi or Bluetooth sender and a PC Windows receiver that "exposes" the azimuth value for easy capture by a simple program (e.g. data logger).
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Some years ago I tried a device from (via Amazon) with a display program that tries to mimic an aircraft attitude indicator. It was disorientating and made me tear my hair out. And anyway this did not let me capture the azimuth value.

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