Rotax 532 radio noise

I have a gyrocopter with a Rotax 532 - My problem is radio noise. As soon as the RPMs are above 5000 there is a constant static noise in my radio. Below 5000 RMPs no noise in my headset. As soon as I hit 5000 it starts.
I have tried different headsets, different radios with no success. I have put shield cable on the spark plug wires and the wires from the engine to the mags. No noticeable change in noise.
I currently bought a ICOM A16B and new headset from NAC. Still noise after 5000.

I think it has something to do with the 532 design and the power curve at 5000 RPMs but that is just a guess. A friend of mine has a 582 and does not experience this problem. His 582 does not have points and a condenser, the 532 does.

Anyone out there who can offer some advice I would greatly appreciate it.

Does the frequency of the noise follow the RPM of the engine? In other words, does it get higher pitched the faster the engine turns?

Had a situation like that on my Fly Baby, and installed a 50,000 microfarad capacitor on the regulator output....
Attachment 9657
Does the trick for me. Just understand it takes a bit for the capacitor to charge, so there'll still be noise for the first minute or so. I get around this by turning on the juice to the alternator before I actually start the engine, just to charge the cap.

Ron Wanttaja

Does the frequency of the noise follow the RPM of the engine? In other words, does it get higher pitched the faster the engine turns?

Had a situation like that on my Fly Baby, and installed a 10,000 microfarad capacitor on the regulator output....
Attachment 9657
Does the trick for me. Just understand it takes a bit for the capacitor to charge, so there'll still be noise for the first minute or so. I get around this by turning on the juice to the alternator before I actually start the engine, just to charge the cap.

Ron Wanttaja

Very often radio noise from 2-stroke engines is caused from a lack of good grounding. Make sure the engine AND the radio are both grounded to the airframe.

The engine is grounded but the radio is a hand held. Not sure how I can ground that

Quote:

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Originally Posted by Gyro727

The engine is grounded but the radio is a hand held. Not sure how I can ground that

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Then I can almost promise that's the problem. Tie a wire around the BNC base of the antenna and tie the other end to the airframe. I bet you a nickel it will reduce if not eliminate your problem.