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Radio Interference

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mike(at)vision499.com
Guest

Posted: Fri Mar 01, 2024 4:36 pm Post subject: Radio Interference

I have a LOM M332 aircraft engine with 2 factory magnetos and an MGL V16 radio.

Antenna is copper foil with balun epoxied into the VS

There are no filters installed.

While listening to ATIS (118.1) there is a ticking sound that is linked to the right magneto, it goes away when right mag is switched off.

No noise when running only on left mag 

While listening to ATIS I can also hear static that is not there on the other frequencies 

I cannot be 100% certain but I think the noise is new.

This noise is not present when listening to Tower (121.9)

Any ideas on what could cause this

 

Thanks

 

Mike

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Ceengland

Joined: 11 Oct 2020
Posts: 391
Location: MS

Posted: Sat Mar 02, 2024 1:56 pm Post subject: Radio Interference

Not knowing that particular engine's characteristics makes it even more difficult to remotely troubleshoot. But here are some generic things to think about.

One thought (but not easiest to check) would be the condenser in the mag. (If it *is* the condenser, you'll be putting points in the mag soon.   ) If the mags are the same or similar to each other, you might be able to swap the condensers between the mags to see if the noise moves to the other mag.

Depending on the plug wire and plug specs, you could have damaged shielding on a plug wire, and/or if the engine uses resistor plugs like a Lyc, you might have a plug going bad.

Then there's the possibility of grounding issues with that mag. Have you done a recent mag check before shutting down to be sure that killing both mags actually kills the engine?  Depending on how the plane is wired, even that might not tell you if a P-lead shield is ungrounded.

Has anything else changed in the wiring of the plane in general? If so, the work could have either removed a needed ground path or added one that wasn't there before, resulting in a 'ground loop' that is affecting the comm.

Just shots in the dark; about the best that can happen 'long distance'.

Virus-free.www.avast.com[url=#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2][/url]



On Fri, Mar 1, 2024 at 6:39 PM <mike(at)vision499.com (mike(at)vision499.com)> wrote:



 	  Quote: 	
		  

I have a LOM M332 aircraft engine with 2 factory magnetos and an MGL V16 radio.

Antenna is copper foil with balun epoxied into the VS

There are no filters installed.

While listening to ATIS (118.1) there is a ticking sound that is linked to the right magneto, it goes away when right mag is switched off.

No noise when running only on left mag 

While listening to ATIS I can also hear static that is not there on the other frequencies 

I cannot be 100% certain but I think the noise is new.

This noise is not present when listening to Tower (121.9)

Any ideas on what could cause this

 

Thanks

 

Mike

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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_________________
Charlie

user9253

Joined: 28 Mar 2008
Posts: 1926
Location: Riley TWP Michigan

Posted: Sat Mar 02, 2024 8:06 pm Post subject: Re: Radio Interference

Try listening using a hand-held radio running on its own internal battery power.

If there is no ignition noise on the hand-held radio, then it can be assumed that 

the noise in the aircraft radio is coming through the aircraft electrical system.

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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_________________
Joe Gores

bob.verwey(at)gmail.com
Guest

Posted: Sun Mar 03, 2024 1:15 am Post subject: Radio Interference

Thanks Charlie this is bankable info



On Sat, 02 Mar 2024, 23:59 Charlie England, <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:



 	  Quote: 	
		  Not knowing that particular engine's characteristics makes it even more difficult to remotely troubleshoot. But here are some generic things to think about.

One thought (but not easiest to check) would be the condenser in the mag. (If it *is* the condenser, you'll be putting points in the mag soon.   ) If the mags are the same or similar to each other, you might be able to swap the condensers between the mags to see if the noise moves to the other mag.

Depending on the plug wire and plug specs, you could have damaged shielding on a plug wire, and/or if the engine uses resistor plugs like a Lyc, you might have a plug going bad.

Then there's the possibility of grounding issues with that mag. Have you done a recent mag check before shutting down to be sure that killing both mags actually kills the engine?  Depending on how the plane is wired, even that might not tell you if a P-lead shield is ungrounded.

Has anything else changed in the wiring of the plane in general? If so, the work could have either removed a needed ground path or added one that wasn't there before, resulting in a 'ground loop' that is affecting the comm.

Just shots in the dark; about the best that can happen 'long distance'.

Virus-free.www.avast.com[url=#m_-8209997907517583625_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2][/url]



On Fri, Mar 1, 2024 at 6:39 PM <mike(at)vision499.com (mike(at)vision499.com)> wrote:



 	  Quote: 	
		  

I have a LOM M332 aircraft engine with 2 factory magnetos and an MGL V16 radio.

Antenna is copper foil with balun epoxied into the VS

There are no filters installed.

While listening to ATIS (118.1) there is a ticking sound that is linked to the right magneto, it goes away when right mag is switched off.

No noise when running only on left mag 

While listening to ATIS I can also hear static that is not there on the other frequencies 

I cannot be 100% certain but I think the noise is new.

This noise is not present when listening to Tower (121.9)

Any ideas on what could cause this

 

Thanks

 

Mike

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

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