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Kitfox IV - Jabiru 2200 - Icom IC-A210 Reciving n

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mprather(at)spro.net
Guest

Posted: Thu Jun 04, 2009 12:44 pm Post subject: Kitfox IV - Jabiru 2200 - Icom IC-A210 Reciving n

Just goes to show you that "shielding everything" isn't a magic bullet.



It's not clear to me from your description that the noise is present when

the radio is receiving as well as transmitting.



Other ideas:

 - Does disconnecting the antenna mitigate received noise?

 - Have you verified that you don't have a "hot mag" by turning off both

ignitions while the engine is running - the engine should quit.  (Maybe

this is normally how you stop the engine - I don't know if your fuel

delivery system allows "idle-cutoff"...)  Additionally, if the noise is

from the ignition system (which I am now doubting), turning both of the

switches off should douse the electrical noise as well.



Regards,



Matt-

 	  Quote: 	
		   

 <post(at)edgeperformance.no>



 I will give it a try tomorrow. But I cant figure what I have done wrong.

Radio is connected right to the battery, all wires out of the molex
	


connector are shielded, jacks to headsets are isolated with plastic

washers through the front panel, have a grounded 50x45cm ground plate

inside the body with the antenna screwed right in the center of the

plate

 	  Quote: 	
		   with the coaxial cable shield grounded straight to the ground plate.



 Heres a really simple sketch of how I have wired my antenna.



 --------

 Kitfox IV w\ Jabiru 2200 Turbo\Aerocarb





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 46820#246820





 Attachments:



 http://forums.matronics.com//files/antenna_ground_plate_163.jpg

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EdgePerformance

Joined: 04 Jun 2009
Posts: 14
Location: Norway

Posted: Thu Jun 04, 2009 1:00 pm Post subject: Re: Kitfox IV - Jabiru 2200 - Icom IC-A210 Recivi

Hi,



i have the aerocarb so normally i use idle-cutoff but both magnetic coils are new and they work fine. Ignition cutoff work great on both cold and hot engine no matter what throttle setting.



What do you mean by antenna mitigate ? My English aren't that great. (Poor Norwegian).



I tried to turn off both ignition switches in flight and the engine didn't get to stop completely before the transmission was over, but I could clearly hear the noise frequency becoming lower. But that could also be both alternator and ignition I believe.



I really hope I can figure this out soon so that I can go out and fly my new build jabiru 2200 turbo kitfox IV.



I only have noise while receiving, other planes can hear me crystal clear ! But I cant hear towers or other planes near by me because this horrible noise.

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_________________
Kitfox IV w\ Jabiru 2200 Turbo\Aerocarb

mprather(at)spro.net
Guest

Posted: Fri Jun 05, 2009 8:38 am Post subject: Kitfox IV - Jabiru 2200 - Icom IC-A210 Reciving n

Hello EdgePerformance,



I'm just suggesting some basic trouble shooting methods.  One of those

methods is to disable possible antagonists - things that might be creating

noise - while still being able to operate the victim.  This can help to

identify which system is the source of the noise.  In turn:



 - Disable the ignition

 - Disable the alternator



To verify that I understand clearly, you simultaneously turned off both

ignitions - causing the engine to stop running, but the prop windmilled

the engine for a short time?  And the noise was still present, though the

frequency was winding down?  I would expect that if the ignition were the

source of the problem, turning the ignition off would instantly stop the

generation of the noise, even as the engine continued to windmill. 

Assuming this suggests to me that the source of the noise is in the

charging system.



Can you turn off the alternator while the engine runs?



Another way of attacking the problem is to identify how the noise is

getting into the victim.



 - Running the radio from a battery can help identify if noise is getting

in through power/ground

 - Disconnecting the antenna (from the back of the radio) can identify if

the noise is coming through the VHF/RF section of the radio



More questions:



 - Do you have a separate audio panel or intercom?  Can you disable it?



 - Does the noise present itself while on the ground (with the engine

running)?  This would make the debug process easier..



 - Is it possible the noise is audio in nature, only (not electrical)? 

Maybe a mic issue?  Disconnect the mic plug from the audio system?



On some Permanent Magnet alternator systems, it is recommended that a

bypass capacitor be installed at the output of the regulator.  A cap with

a value of 10kuF with at least a 40V rating would be adequate.



I apologize if it seems I'm repeating myself..  I just want to make sure

my non-existent Norwegian isn't causing a communication problem.  

Regards,



Matt-



 	  Quote: 	
		   

 <post(at)edgeperformance.no>



 Hi,



 i have the aerocarb so normally i use idle-cutoff but both magnetic

coils
	


 	  Quote: 	
		   are new and they work fine. Ignition cutoff work great on both cold and

hot engine no matter what throttle setting.
	


 	  Quote: 	
		  

 What do you mean by antenna mitigate ? My English aren't that great.

(Poor
	


 	  Quote: 	
		   Norwegian).



 I tried to turn off both ignition switches in flight and the engine

didn't
	


 	  Quote: 	
		   get to stop completely before the transmission was over, but I could

clearly hear the noise frequency becoming lower. But that could also be
	


both alternator and ignition I believe.

 	  Quote: 	
		  

 I really hope I can figure this out soon so that I can go out and fly my

new build jabiru 2200 turbo kitfox IV.
	


 	  Quote: 	
		  

 --------

 Kitfox IV w\ Jabiru 2200 Turbo\Aerocarb





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 46830#246830

- 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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EdgePerformance

Joined: 04 Jun 2009
Posts: 14
Location: Norway

Posted: Fri Jun 05, 2009 1:10 pm Post subject: Re: Kitfox IV - Jabiru 2200 - Icom IC-A210 Recivi

Hi Matt,



Thanks alot for all suggestions. Yes I believe it may be alternator noise as the prop did windmill for a few second while I was receiving a transmission. I have fully charged my battery now, and will try to take a landing circuit with the alternator wires disconnected.



I use the integrated intercom in my Icom IC-A210 transceiver witch works exceptionally great. The intercom and transmissions are crystall clear. 



The noise does exist on ground, but it seems to affect the radio noise even more as in flight.



I will try out all suggestions tomorrow and come back with a test resault. I have also got hold on a new RA-Miller com antenna I will try as well as a completly isolated battery. 



Thanks again,

Thomas

 	  intercom(at)spro.net wrote: 	
		  Hello EdgePerformance,



I'm just suggesting some basic trouble shooting methods.  One of those

methods is to disable possible antagonists - things that might be creating

noise - while still being able to operate the victim.  This can help to

identify which system is the source of the noise.  In turn:



 - Disable the ignition

 - Disable the alternator



To verify that I understand clearly, you simultaneously turned off both

ignitions - causing the engine to stop running, but the prop windmilled

the engine for a short time?  And the noise was still present, though the

frequency was winding down?  I would expect that if the ignition were the

source of the problem, turning the ignition off would instantly stop the

generation of the noise, even as the engine continued to windmill. 

Assuming this suggests to me that the source of the noise is in the

charging system.



Can you turn off the alternator while the engine runs?



Another way of attacking the problem is to identify how the noise is

getting into the victim.



 - Running the radio from a battery can help identify if noise is getting

in through power/ground

 - Disconnecting the antenna (from the back of the radio) can identify if

the noise is coming through the VHF/RF section of the radio



More questions:



 - Do you have a separate audio panel or intercom?  Can you disable it?



 - Does the noise present itself while on the ground (with the engine

running)?  This would make the debug process easier..



 - Is it possible the noise is audio in nature, only (not electrical)? 

Maybe a mic issue?  Disconnect the mic plug from the audio system?



On some Permanent Magnet alternator systems, it is recommended that a

bypass capacitor be installed at the output of the regulator.  A cap with

a value of 10kuF with at least a 40V rating would be adequate.



I apologize if it seems I'm repeating myself..  I just want to make sure

my non-existent Norwegian isn't causing a communication problem.  

Regards,



Matt-



 	  Quote: 	
		   

 <post>



 Hi,



 i have the aerocarb so normally i use idle-cutoff but both magnetic

coils

	


 	  Quote: 	
		   are new and they work fine. Ignition cutoff work great on both cold and

hot engine no matter what throttle setting.

	


 	  Quote: 	
		  

 What do you mean by antenna mitigate ? My English aren't that great.

(Poor

	


 	  Quote: 	
		   Norwegian).



 I tried to turn off both ignition switches in flight and the engine

didn't

	


 	  Quote: 	
		   get to stop completely before the transmission was over, but I could

clearly hear the noise frequency becoming lower. But that could also be

	


both alternator and ignition I believe.

 	  Quote: 	
		  

 I really hope I can figure this out soon so that I can go out and fly my

new build jabiru 2200 turbo kitfox IV.

	


 	  Quote: 	
		  

 --------

 Kitfox IV w\ Jabiru 2200 Turbo\Aerocarb





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 46830#246830

- 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

_________________
Kitfox IV w\ Jabiru 2200 Turbo\Aerocarb

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