If it is the ramp-up PWM modulation, then I guess worst case is to somehow put a muffler box around the motor to keep the neighbors happy. But the vibrations are probbbly well couipled to the shafts and antenna system, so just muffling the motor might be not as effective. Wrap a towel around the motor for a quick test and see how much that attenuates the noise.

Bob

-----Original Message----- From: AMSAT-BB amsat-bb-bounces@amsat.org On Behalf Of Burns Fisher via AMSAT-BB Sent: Friday, March 27, 2020 3:04 PM To: Kevin wa7fwf@gmail.com Cc: AMSAT BB amsat-bb@amsat.org Subject: Re: [amsat-bb] AlphaSpid Green Heron rotor controller PstRotator

Is the Alfa-Spid stepper motor based? Certainly the feedback is digital. But I could certainly imagine a bunch of fast steps sounds like a beep.

My G5500 actually makes a slightly odd noise too. I sounds almost like a clock being wound. I'm guessing it has something to do with the brake?? Does the A-S have one?

Maybe sound insulation is going to be your best bet.

On Thu, Mar 26, 2020 at 9:10 PM Kevin via AMSAT-BB amsat-bb@amsat.org wrote:

I do not own one but looking at the documentation for the controller I noticed this, "gradual startup and shutdown of rotor power to reduce stress on towers, antennas and rotors. This is achieved by pulse-width-modulating the operating voltage for the rotor."

That could very well be the source of the "beeping" with the windings in the motor singing.

73 Kevin WA7FWF

On 3/26/2020 17:47, Jeff via AMSAT-BB wrote:

...

Green Heron R-21 controller

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_______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb