Matronics Email Lists :: View topic - RE-POST: Magneto Noise

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

RE-POST: Magneto Noise

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

jluckey(at)pacbell.net
Guest

Posted: Fri Apr 25, 2014 11:58 am Post subject: RE-POST: Magneto Noise

Per request from J. Davis...





     ----- Forwarded Message -----

   From: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com>

 To: aeroelectric-list(at)matronics.com 

 Sent: Tuesday, April 8, 2014 8:06 AM

 Subject: Re:  Magneto Noise

  

 

--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>



At 12:04 PM 4/6/2014, you wrote:



I flew w/ a friend recently and when trying to get awos for our 

destination airport (which is a pretty weak signal) it was almost 

impossible to hear due to magneto noise.  The radio is a Garmin 430W 

in a Cherokee and we were around 10 miles from the airport.  When we 

got within 3 or 4 miles the signal was much clearer.  All other 

transmissions with ATC & towers were acceptable but I noticed at high 

volume I could clearly hear magneto noise in the background.



I'm wondering if that's just the way it is or if there is a problem 

with the magnetos or P lead  wiring.



    Was this a new condition or has it been that

    way 'forever'. It's difficult for the neophyte

    observer to tell the difference between ignition

    noises getting into the system by way of plug wire

    radiation versus p-lead radiation.



    First, make sure that the perceived noise goes up

    and down with volume control settings on radio.

    This all but guarantees that it's coming in through

    the antenna.



    Then, disconnect both p-leads from the back of the

    magnetos and run the engine. See if the noise is

    still heard . . . turn to unused frequency . . .

    open squelch.



    If you can still hear it, then look for bad plug

    wire. If not, hook up one p-lead at a time and

    repeat experiment . .  . see if noise is predicated

    on either or both of the p-leads being hooked up.



    Once you've identified the offending radiator,

    you need to figure out why. If this is a 'new'

    condition, then you're looking for something that

    has changed. Bad cap in mag (probably not both)

    broken ground lead on p-lead shield. If possible/

    practical wire p-lead wires per Figure Z-27



http://tinyurl.com/n3oy37f



    Ground p-lead shields at magneto end only . . .

    use p-lead shields to ground mag switch. Remove

    and existing ground to the mag switch.



    If the noise is coming from both p-leads,

    there are 'approved' magneto noise filters



http://tinyurl.com/l3s4mrj



    that most mechanics will install with a simple

    log-book entry.



    Bob . . .

   Bob . . .  



 	  Quote: 	
		   <a href="http://www.matronics.com/Navigator?AeroElectric-List" targe also available via the Web                -Matt Dralle, List Admin.=======

- 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

jwd3ca(at)gmail.com
Guest

Posted: Fri Apr 25, 2014 12:13 pm Post subject: RE-POST: Magneto Noise

Thanks, Jeff. I was thinking it had to do with ignition issues (rather than radio noise )Â  but I'll file it away for future reference.  On 25 Apr 2014 16:08, "Jeff Luckey" <jluckey(at)pacbell.net (jluckey(at)pacbell.net)> wrote:[quote] Per request from J. Davis...

 



     ----- Forwarded Message -----

    From: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>

 To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com) 

  Sent: Tuesday, April 8, 2014 8:06 AM

 Subject: Re:  Magneto Noise

  

 

--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>

 

At 12:04 PM 4/6/2014, you wrote:



I flew w/ a friend recently and when trying to get awos for our 

destination airport (which is a pretty weak signal) it was almost 

impossible to hear due to magneto noise.Â  The radio is a Garmin 430W 

 in a Cherokee and we were around 10 miles from the airport.Â  When we 

got within 3 or 4 miles the signal was much clearer.Â  All other 

transmissions with ATC & towers were acceptable but I noticed at high 

volume I could clearly hear magneto noise in the background.

 

I'm wondering if that's just the way it is or if there is a problem 

with the magnetos or P lead  wiring.



Â  Â  Was this a new condition or has it been that

Â  Â  way 'forever'. It's difficult for the neophyte

Â  Â  observer to tell the difference between ignition

Â  Â  noises getting into the system by way of plug wire

 Â  Â  radiation versus p-lead radiation.



Â  Â  First, make sure that the perceived noise goes up

Â  Â  and down with volume control settings on radio.

Â  Â  This all but guarantees that it's coming in through

 Â  Â  the antenna.



Â  Â  Then, disconnect both p-leads from the back of the

Â  Â  magnetos and run the engine. See if the noise is

Â  Â  still heard . . . turn to unused frequency . . .

Â  Â  open squelch.



Â  Â  If you can still hear it, then look for bad plug

 Â  Â  wire. If not, hook up one p-lead at a time and

Â  Â  repeat experiment . .  . see if noise is predicated

Â  Â  on either or both of the p-leads being hooked up.



Â  Â  Once you've identified the offending radiator,

Â  Â  you need to figure out why. If this is a 'new'

Â  Â  condition, then you're looking for something that

 Â  Â  has changed. Bad cap in mag (probably not both)

Â  Â  broken ground lead on p-lead shield. If possible/

Â  Â  practical wire p-lead wires per Figure Z-27



http://tinyurl.com/n3oy37f

 

Â  Â  Ground p-lead shields at magneto end only . . .

Â  Â  use p-lead shields to ground mag switch. Remove

Â  Â  and existing ground to the mag switch.



Â  Â  If the noise is coming from both p-leads,

Â  Â  there are 'approved' magneto noise filters

 

http://tinyurl.com/l3s4mrj



Â  Â  that most mechanics will install with a simple

Â  Â  log-book entry.



Â  Â  Bob . . .

Â   Bob . . .Â  



 > 



 

 

  



  	  Quote: 	
		  



ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List

tp://forums.matronics.com

_blank">http://www.matronics.com/contribution



	
[b]

- 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

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum