Engine noise

[GolfWhiskeyHotel]

Flying a friends Aerostar a few days ago. Really nice ,But the radio......Loud engine (912uls) related noise (change of pitch when increasing revs) Except when I transmit, then all is quiet. No-one complaining of poor reception.  Difficult to hear other's transmissions. Where would I start to look for the problem. Regulator has the large capacitor attached. Radio is ICOM 200. Thanks

G

[facthunter]

Topic should be Engine Radio Interference. Nev

[IBob]

You may want to check how the 'mag' switches are wired. Unless they are as per Rotax installation instructions, with correct shielding, they can make for radio noise.

[Blueadventures]

19 hours ago, GolfWhiskeyHotel said:

Flying a friends Aerostar a few days ago. Really nice ,But the radio......Loud engine (912uls) related noise (change of pitch when increasing revs) Except when I transmit, then all is quiet. No-one complaining of poor reception.  Difficult to hear other's transmissions. Where would I start to look for the problem. Regulator has the large capacitor attached. Radio is ICOM 200. Thanks

G

Worth buying a new capacitor, even if not the cause its not an expensive outlay.  Often the issue is a faulty capacitor.  Need to be the correct size and also check its wiring circuit.

[BrendAn]

2 hours ago, facthunter said:

Topic should be Engine Radio Interference. Nev

Wouldn't it be better if you gave him some helpful advice

Edited Wednesday at 06:53 AM by BrendAn

[facthunter]

I know what I don't know and Radio was never one of my strong points but I thought calling it Interference would be HELPFUL as Engine Noise is just engine Noise. Nev

[sfGnome]

On 31/3/2026 at 10:03 PM, GolfWhiskeyHotel said:

Flying a friends Aerostar a few days ago. Really nice ,But the radio......Loud engine (912uls) related noise

Has it always done that, or is this a new thing? Knowing that may help to ascertain whether it is a build problem (like unshielded mag wires) or a failure issue (like an old cap or a crook earth, etc). 

[skippydiesel]

"Engine noise" - if its electrical interference, this is something other than engine noise as in  -  ignition, charging/stator.........😈

[phonetic]

On 31/03/2026 at 10:03 PM, GolfWhiskeyHotel said:

Flying a friends Aerostar a few days ago. Really nice ,But the radio......Loud engine (912uls) related noise (change of pitch when increasing revs)

sounds like alternator whine sound, do other stations report the whine on your transmissions or just in your reception 

[GolfWhiskeyHotel]

On 02/04/2026 at 11:27 AM, skippydiesel said:

"Engine noise" - if its electrical interference, this is something other than engine noise as in  -  ignition, charging/stator.........😈

FFS.................. I wrote    " But the radio . - Loud engine related noise "  I didnt know I needed to be so specific as to rule out the engine  , I would have thought  people could have sussed that I meant interference.... However I appear to be wrong. 

[GolfWhiskeyHotel]

On 02/04/2026 at 10:48 AM, sfGnome said:

Has it always done that, or is this a new thing? Knowing that may help to ascertain whether it is a build problem (like unshielded mag wires) or a failure issue (like an old cap or a crook earth, etc). 

THis is a Rotax engine. so mags and caps are out.  The sound is a high pitched whine (through the headphones, constantly ). It must have been doing it for quite a while. I was always a passenger and never took any notice of it.  Its the alternator or reg/rec I'm sure, But what to do about it? Maybe that Large capacitor is cactus?      Pulling the dash out and fitting ferrite beads and filters is going to be quite a job.  I was hoping that I could get some advice on in what direction to look.   Thanks. G

[GolfWhiskeyHotel]

20 hours ago, phonetic said:

sounds like alternator whine sound, do other stations report the whine on your transmissions or just in your reception 

It seems to be reception only, no-one has complained about my transmissions, But I will get a radio check tomorrow.  When I press the PTT button to transmit the radio is as clear as a bell and all interference stops.  

[facthunter]

I'm JUST trying to Get the correct responses to your Problem. Changing the thread starter would have aided this. Interference seems to be Much More of an Issue than when everything was shielded. Permanent magnet alternator regulation a new Problem? Nev

[BurnieM]

55 minutes ago, GolfWhiskeyHotel said:

It seems to be reception only, no-one has complained about my transmissions, But I will get a radio check tomorrow.  When I press the PTT button to transmit the radio is as clear as a bell and all interference stops.  

Does not really tell you much. PTT disconnects the receiver.

 

[rgmwa]

Do pilot and passenger headsets both do the same thing? If only one, then maybe start with checking the headset jack connections.  Just a guess.