Rotax 532 radio noise

[Gyro727]

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.

[rwanttaja]

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....

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

[rwanttaja]

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....

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

[melann]

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.