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		hgmckay
 
 
  Joined: 23 May 2006 Posts: 397
 
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				 Posted: Tue Mar 31, 2015 12:27 pm    Post subject: Engine noise in Radio and Headset | 
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				I have an Allegro 2000 E-LSA with a Rotax 912 UL engine using the standard  Rotax Voltage regulator. After 600 +/- hours I am getting a lot of “noise” in my  head sets when I use the radio push-to-talk transmit button. The radio is an  ICOM IC-A200 VHF Transceiver using a Comant CI 121 VHF Antenna. When using the  P-T button to transmit I can actually hear the engine rpm, especially at low  rpms. At higher rpms the noise is not as bad but it is still there as noise. The  voltage regulator is wired per the Rotax engine wiring diagram with the addition  of two 10,000 Mf capacitors in parallel.
   
  Can anyone give me advice as to how to eliminate this “noise”?
   
  Hugh G.  McKay III, P.E. Fellow, L.M. ASCE
 Senior Consultant
 Worldwide Engineering  Inc.
 4090 North NC Hwy. 16
 Denver, NC 28037
 
 Ph. 704-661-8271
 Fax  704-483-5466
 email hgmckay(at)bellsouth.net
 Allegro 2000 E-LSA N661WW
  Rotax 912  UL 689 hours
 
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		ledson
 
  
  Joined: 29 Apr 2009 Posts: 62
 
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				 Posted: Tue Mar 31, 2015 5:41 pm    Post subject: Engine noise in Radio and Headset | 
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				Hugh, 
 I would check the noise canceling capacitors.  They do fail with exposure to heat and humidity and they are not hard to check.
 The following document will help you to understand the various failure modes of the different types of capacitors. 
 
 http://www.electrocube.com/electrocube/assets/File/documentation-files/capacitor-documents/electrocube-tech-bulletin-why-capacitors-fail.pdf 
 Good luck, 
 Larry Edson
 N4362C
 
 Sent from my iPad
 
 On Mar 31, 2015, at 4:26 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
 [quote]    I have an Allegro 2000 E-LSA with a Rotax 912 UL engine using the standard  Rotax Voltage regulator. After 600 +/- hours I am getting a lot of “noise” in my  head sets when I use the radio push-to-talk transmit button. The radio is an  ICOM IC-A200 VHF Transceiver using a Comant CI 121 VHF Antenna. When using the  P-T button to transmit I can actually hear the engine rpm, especially at low  rpms. At higher rpms the noise is not as bad but it is still there as noise. The  voltage regulator is wired per the Rotax engine wiring diagram with the addition  of two 10,000 Mf capacitors in parallel.
   
  Can anyone give me advice as to how to eliminate this “noise”?
   
  Hugh G.  McKay III, P.E. Fellow, L.M. ASCE
 Senior Consultant
 Worldwide Engineering  Inc.
 4090 North NC Hwy. 16
 Denver, NC 28037
 
 Ph. 704-661-8271
 Fax  704-483-5466
 email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
 Allegro 2000 E-LSA N661WW
  Rotax 912  UL 689 hours
  
  
 <Hugh.vcf>
 [b]
 
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		brian.davies(at)clara.co. Guest
 
 
 
 
 
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				 Posted: Wed Apr 01, 2015 12:34 am    Post subject: Engine noise in Radio and Headset | 
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				Also worth checking all the earth connections, including the aerial for corrosion, not just visually. Undo and clean all connections.  Particularly, check the regulator earth.
  
 Regards
  
 Brian Davies
  
 From: owner-rotaxengines-list-server(at)matronics.com [mailto:owner-rotaxengines-list-server(at)matronics.com] On Behalf Of Larry Edson
 Sent: 01 April 2015 02:41
 To: rotaxengines-list(at)matronics.com
 Subject: Re: Engine noise in Radio and Headset 
  
 Hugh, 
 
  
 
 I would check the noise canceling capacitors.  They do fail with exposure to heat and humidity and they are not hard to check.
 
 The following document will help you to understand the various failure modes of the different types of capacitors. 
 
 http://www.electrocube.com/electrocube/assets/File/documentation-files/capacitor-documents/electrocube-tech-bulletin-why-capacitors-fail.pdf 
 
  
 
 Good luck, 
 
  
 
 Larry Edson
 
 N4362C
 Sent from my iPad
 On Mar 31, 2015, at 4:26 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
  	  | Quote: | 	 		  
 I have an Allegro 2000 E-LSA with a Rotax 912 UL engine using the standard Rotax Voltage regulator. After 600 +/- hours I am getting a lot of “noise” in my head sets when I use the radio push-to-talk transmit button. The radio is an ICOM IC-A200 VHF Transceiver using a Comant CI 121 VHF Antenna. When using the P-T button to transmit I can actually hear the engine rpm, especially at low rpms. At higher rpms the noise is not as bad but it is still there as noise. The voltage regulator is wired per the Rotax engine wiring diagram with the addition of two 10,000 Mf capacitors in parallel.
 
  
 
 Can anyone give me advice as to how to eliminate this “noise”?
 
  
 
 Hugh G. McKay III, P.E. Fellow, L.M. ASCE
 Senior Consultant
 Worldwide Engineering Inc.
 4090 North NC Hwy. 16
 Denver, NC 28037
 
 Ph. 704-661-8271
 Fax 704-483-5466
 email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
 Allegro 2000 E-LSA N661WW
 
 Rotax 912 UL 689 hours
 
  
 
 
 <Hugh.vcf>
   http://www.matronics.com/Navigator?RotaxEngines-List  | 	  01234567
   [quote][b]
 
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