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Alternator Whine in Radio Transmit

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Ron Lendon

Joined: 10 Jan 2006
Posts: 685
Location: Clinton Twp., MI

Posted: Sun Sep 08, 2013 3:11 pm Post subject: Alternator Whine in Radio Transmit

Bob,



I have the WW Corvair engine in a 601XLB and have 180 hours on it.  I used your design with the JD alternator and replaced the voltage regulator/rectifier with the B&C unit "PMR1C-14".  At about 170 hours the filter cap 10,000uF gave up and the ATC folks started to complain.



I have replaced the Cap and now that I know about the whine I find I can switch off the alternator during transmit and it is as clear as a bell.  With the alternator switched on it does have a whine that is tolerable, but it still has a whine.



What steps can I take to eliminate the whine from the alternator and leave it switched on?



Be gentle, I'm a metal worker not an electrician.

_________________
Ron Lendon
WW Corvair with Roy's Garage 5th bearing
CH 601 XLB
N601LT - Flying
http://www.mykitlog.com/rlendon
Corvair Engine Prints:
https://sites.google.com/site/corvairenginedata/

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Sep 09, 2013 5:49 am Post subject: Alternator Whine in Radio Transmit

At 06:11 PM 9/8/2013, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "Ron Lendon" <ron.lendon(at)gmail.com>



 Bob,



 I have the WW Corvair engine in a 601XLB and have 180 hours on it.  I used your design with the JD alternator and replaced the voltage regulator/rectifier with the B&C unit "PMR1C-14".  At about 170 hours the filter cap 10,000uF gave up and the ATC folks started to complain.



 I have replaced the Cap and now that I know about the whine I find I can switch off the alternator during transmit and it is as clear as a bell.  With the alternator switched on it does have a whine that is tolerable, but it still has a whine.



 What steps can I take to eliminate the whine from the alternator and leave it switched on?



 Be gentle, I'm a metal worker not an electrician. 	


   It's it only on transmit? Do you hear it in the headsets

   for receiving other stations?  Suggest you check the microphone

   and headset jacks for being grounded to the panel . . . these

   should be insulated from the panel and grounded through wires

   back to the intercom.



   You can get insulating washers from B&C



    



 

 

   Bob . . .    [quote][b]

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Mon Sep 09, 2013 7:13 am Post subject: Re: Alternator Whine in Radio Transmit

Link to B & C insulating washers for headset and mic jacks.

http://www.bandc.biz/insulatingwasherset1pair.aspx

_________________
Joe Gores

Ron Lendon

Joined: 10 Jan 2006
Posts: 685
Location: Clinton Twp., MI

Posted: Mon Sep 09, 2013 12:26 pm Post subject: Re: Alternator Whine in Radio Transmit

The head sets jacks are insulated and grounded back to the single point ground with everything else.  Do I need to move that ground wire directly to the intercom unit?



It is only on transmit, I have tried other channels but it makes no difference pilot or copilot, same thing.

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Tue Sep 10, 2013 4:33 am Post subject: Re: Alternator Whine in Radio Transmit

During a phone conversation with Ron Lendon, I learned that shielded wire was not used for the mic jack.  I am thinking that replacing the two individual wires with shielded cable might not help reduce the alternator whine.  Bob, I would appreciate your comments on the advantages of shielded wire for the mic jack.

Thanks, Joe

_________________
Joe Gores

cyav8r(at)yahoo.com
Guest

Posted: Tue Sep 10, 2013 5:48 am Post subject: Alternator Whine in Radio Transmit

I was planning to be over in the morning, but probably leaving early afternoon.

Where is the waiver doc for sign-ins?



pt

        From: user9253 <fransew(at)gmail.com>

 To: aeroelectric-list(at)matronics.com 

 Sent: Tuesday, September 10, 2013 7:33 AM

 Subject: Re: Alternator Whine in Radio Transmit

  

 

--> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>



During a phone conversation with Ron Lendon, I learned that shielded wire was not used for the mic jack.  I am thinking that replacing the two individual wires with shielded cable might not help reduce the alternator whine.  Bob, I would appreciate your comments on the advantages of shielded wire for the mic jack.

Thanks, Joe



--------

Joe Gores





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=408331#408331http://www.matronics.com/Navigat=               - MATRONICS WEB FORUMS href="http://forums.matronics.com/" target="_blank">http://forums.matr                     &nbs//www.matronics.com/contribution" target="_blank">http://www.matronics.co==================

 

 

  

 [quote][b]

cyav8r(at)yahoo.com
Guest

Posted: Tue Sep 10, 2013 6:22 am Post subject: Alternator Whine in Radio Transmit

Sucks when you reply to the wrong email...



sorry





        From: Paul Thomson <cyav8r(at)yahoo.com>

 To: "aeroelectric-list(at)matronics.com" <aeroelectric-list(at)matronics.com> 

 Sent: Tuesday, September 10, 2013 8:46 AM

 Subject: Re: Re: Alternator Whine in Radio Transmit

  

 

I was planning to be over in the morning, but probably leaving early afternoon.

Where is the waiver doc for sign-ins?



pt

        From: user9253 <fransew(at)gmail.com>

 To:  aeroelectric-list(at)matronics.com 

 Sent: Tuesday, September 10, 2013 7:33 AM

 Subject: Re: Alternator Whine in Radio Transmit

  

 

--> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>



During a phone conversation with Ron Lendon, I learned that shielded wire was not used for the mic jack.  I am thinking that replacing the two individual wires with shielded cable might not help reduce the alternator whine.  Bob, I would appreciate your comments on the advantages of shielded wire for the mic jack.

Thanks, Joe



--------

Joe Gores





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=408331#408331 http://www.matronics.com/Navigat=               - MATRONICS WEB FORUMS href="http://forums.matronics.com/" target="_blank">http://forums.matr                     &nbs//www.matronics.com/contribution" target="_blank">http://www.matronics.co==================

 

 

  

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

_target="_blank" href="http://www.matronics.com/contribution">http://www======================


	






 

 

  

 [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Sep 10, 2013 9:22 am Post subject: Alternator Whine in Radio Transmit

At 07:33 AM 9/10/2013, you wrote:

 	  Quote: 	
		  



During a phone conversation with Ron Lendon, I learned that shielded 

wire was not used for the mic jack.  I am thinking that replacing 

the two individual wires with shielded cable might not help reduce 

the alternator whine.  Bob, I would appreciate your comments on the 

advantages of shielded wire for the mic jack.

Thanks, Joe



--------

Joe Gores


	


   Shielded wire is 99.9% probability of NOT being

   the solution. Shielding breaks a capacitive coupling

   between a strong antagonist wire with large, fast

   rise signals on it and some vulnerable victim carrying

   small, easily corrupted signals.



   Alternator noise coupled into a vulnerable system

   is most likely to be bus noise to a poorly qualified

   device, magnetically coupled from some fat wire carrying

   alternator current, or a ground loop.



   Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Sep 10, 2013 9:24 am Post subject: Alternator Whine in Radio Transmit

At 03:26 PM 9/9/2013, you wrote:

 	  Quote: 	
		  



The head sets jacks are insulated and grounded back to the single 

point ground with everything else.  Do I need to move that ground 

wire directly to the intercom unit?


	


   Yes.

   Bob . . .

Ron Lendon

Joined: 10 Jan 2006
Posts: 685
Location: Clinton Twp., MI

Posted: Sat Sep 14, 2013 3:29 am Post subject: Re: Alternator Whine in Radio Transmit

Thanks Bob,



This is the part of the instructions from the Sigtronics Installation instructions I missed.



2.  Connect all intercom mic jack grounds to a single aircraft chassis ground point - Intercom Central ground Point â€œAâ€ - as shown in Figure 4. (Use the black washers supplied to insulate the intercom mic jacks from aircraft chassis ground). Note this intercom central grounding point is used to eliminate any unwanted electrical noises, such as alternator whine or strobe noise, from being induced into the intercom system through the grounds. All intercom mic jack barrels must be insulated from ground where they are mounted and connected back to Intercom Central Ground Point â€œAâ€ on their own individual ground wire. Similarly, both intercom ground wires (J1 pin 4) and the push-to-transmit switch grounds must also be connected back to Intercom Central Ground Point â€œAâ€ . It is not necessary, however, to connect the headphone jack barrels to Intercom Central Ground Point â€œAâ€ . They can either be grounded where they are mounted or some place nearby.



I have the airplane opened up and will remedy this oversight promptly.

Ron Lendon

Joined: 10 Jan 2006
Posts: 685
Location: Clinton Twp., MI

Posted: Fri Nov 22, 2013 11:36 am Post subject: Re: Alternator Whine in Radio Transmit

Bob and all,



What really made the whine go away was adding a ground wire from the battery through the firewall to the engine.  Even though I have a metal airframe it still needed the ground wire.  The battery is located behind the passenger seat and the airframe was prime on all the flanges before assembly. The battery was grounded directly to the airframe with a short wire and it really wasn't working very well.  The starter spins better also with this setup.

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Nov 22, 2013 7:45 pm Post subject: Alternator Whine in Radio Transmit

At 01:36 PM 11/22/2013, you wrote:

 	  Quote: 	
		  



Bob and all,



What really made the whine go away was adding a ground wire from the 

battery through the firewall to the engine.  Even though I have a 

metal airframe it still needed the ground wire.  The battery is 

located behind the passenger seat and the airframe was prime on all 

the flanges before assembly. The battery was grounded directly to 

the airframe with a short wire and it really wasn't working very 

well.  The starter spins better also with this setup.


	


   The 'star' system for single point grounds

   radiate from the fire-wall ground penetration

   where goodies on both sides come to a single

   point. Your high resistance structure produced

   demonstrably poor cranking performance and

   laid the foundation for a really strong

   ground loop for alternator ripple to generate

   noise voltages.



   I'm sorry we didn't ask you about your ground

   system architecture earlier.

   Bob . . .

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