Matronics Email Lists :: View topic - Ignition Interference

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

Ignition Interference

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Sun Apr 29, 2012 9:31 pm Post subject: Ignition Interference

My test pilot flew my plane for the first time today. Yeah! But now I have to fix all the problems that we've ignored. First on the list is the RFI issue. I have a Jabiru 3300 in my Sonex. Wired it more or less like Bob's diagrams, with a filter capacitor. Ran all my power in on the right side and the two mag wires in on the left. Mag wires are 1-conductor shielded, with the braid pulled out the last 2 or 3 inches on either end. Seems like it's the left mag, cuz when it's turned off, the noise disappears. Suggestions?

_________________
Dan

stearman456

Joined: 14 Aug 2010
Posts: 49

Posted: Mon Apr 30, 2012 5:52 am Post subject: Re: Ignition Interference

If you have two mags and a filter on each one, the quickest thing to try is swapping the filters.  I had a dud filter once a couple of years ago straight out of the box.

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Mon Apr 30, 2012 6:26 am Post subject: Re: Ignition Interference

There are no filters on either mag. The filter capacitor is on the alternator. You think putting a filter capacitor on the offending mag wire might work?

_________________
Dan

stearman456

Joined: 14 Aug 2010
Posts: 49

Posted: Mon Apr 30, 2012 6:35 am Post subject: Re: Ignition Interference

I put a filter on each of mine (Continental C90 with Bendix mags) and that cleared up my noise.  I had one dud filter at first but after replacing it she's nice and quiet now.  In Bob's book there is some good troubleshooting advice for radio noise: page 16-13 of Rev 12.



Dan

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Mon Apr 30, 2012 7:50 am Post subject: Re: Ignition Interference

Yes, thanks for pointing this out. Sounds like I could disconnect the P lead of the left mag and see if it still makes noise. If it does, then Bob says it's getting out through the P lead wiring. If that's the case, sounds like replacing the single conductor wire P lead and ground shield would work. That's not a huge undertaking, but maybe it could be avoided if I slapped one of my ferrite beads on the switch end of the offending P lead and ground?



If the noise doesn't go away, then the 'plug harnesses are suspect'



Plug harnesses may be electrically tested (continuity between end of center conductor and between ends of shield braid). Unhook individual plug wires and do a continuity check between the spark plug connector shell (attaches to shield) and engine crankcase.  



I don't quite understand what's being asked for, since I don't have a spark plug wire handy and haven't really looked to see how the wires are made. Sounds like it's a single conductor shielded wire. Is there to be no continuity between the inner conductor and the shell?



Does the ignition noise change in intensity as the receiver's volume control is adjusted? If so, the noise is probably radiated and coming in through the antenna system along with desired signals.



I'll ask my pilot, but I'd think a normal response to an increase in volume control would be and increase in volume of all signals coming in, good or bad, and would not necessarily point to the antenna.

_________________
Dan

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Tue May 01, 2012 12:50 pm Post subject: Re: Ignition Interference

Ignition noise problem updated



Problem



I hear that distinctive spark plug interference noise when I listen to the radio. As expected, it varies with RPM. When I turn off the left magneto, 95% of the noise goes away, leaving a tolerable feint interference noise from the right magneto system. I disconnected the P-lead from it's fast on tab of the left (noisy) magneto giving me a hot mag. This had no effect on the noise. After reconnecting the left P lead, I disconnected the right P lead the same way, which also had no effect. This tells me the P leads aren't causing the noise. 



Distrubutor, Spark Plugs, and Spark Plug Wires



I considered connecting the high intensity wire from the left mag to the right distributor, but it's an inch or so short. I run into the same problems with reach when thinking about switching the 6 plug wires from the left distributor with the 6 wires from the right. But this may yet be possible. It's that I sorta cringe at having to pull all the wires from behind the tight space in back of the engine. I'll take another look when I get back to the plane. I'm at the airport at a wifi hot spot a half mile away from my hangar.



I could also check the resistance of the spark plug wires. These came with the engine when I bought it at 50 hours. They are Champion 8.0mm(?) that I believe are shielded. It looks like there are vast differences in resistance depending on what type of wires I have. I'm not aware of the normal range for my wires, but will check them anyway. The longer wires should at least have more resistance than the shorter ones.



If I can get to the shields of my spark plug wires, I'll test them for continuity with the inner conductor. I didn't think the shield is supposed to be connected to the condutor. A normal shielded wire doesn't have the shield carrying any current. It is grounded at one end and open at the other. But I don't see how that can be arranged with a spark plug wire. Where is the ground connection for this? In the spark plug? In the distributor cap?



I also talked with an A&P next door about my problem. He said my NGK automotive spark plugs aren't high resistive, which means they're noisy. Suggested checking the resistance and/or replacing with aviation spark plugs. Might this possibly be a solution to my problem?



Antenna System



I've read the antenna system could be at fault if the noise increases when the volume control is increased. I'm not sure if I understand that. Isn't the volume control just effecting the gain of all signals, ignition noise or otherwise? 



The radio has a shielded antenna cable from the belly mount to the back of the radio. If it fits, I might be able to put a ferrite bead over the end of the antenna cable. Or over the wires going from the radio to the headset jack on the panel.



Any help would be appreciated!



PS: Dan mentioned a mag filter worked. Does this go on the P lead? If so how does it work, by stopping the P lead from acting like an antenna? Since my noise goes away when the P lead is unplugged, seems like it wouldn't work for me.

_________________
Dan

ceengland(at)bellsouth.ne
Guest

Posted: Tue May 01, 2012 2:47 pm Post subject: Ignition Interference

On 05/01/2012 03:50 PM, messydeer wrote:

 	  Quote: 	
		   



 Ignition noise problem updated



 Problem



 I hear that distinctive spark plug interference noise when I listen to the radio. As expected, it varies with RPM. When I turn off the left magneto, 95% of the noise goes away, leaving a tolerable feint interference noise from the right magneto system. I disconnected the P-lead from it's fast on tab of the left (noisy) magneto giving me a hot mag. This had no effect on the noise. After reconnecting the left P lead, I disconnected the right P lead the same way, which also had no effect. This tells me the P leads aren't causing the noise.



 Distrubutor, Spark Plugs, and Spark Plug Wires



 I considered connecting the high intensity wire from the left mag to the right distributor, but it's an inch or so short. I run into the same problems with reach when thinking about switching the 6 plug wires from the left distributor with the 6 wires from the right. But this may yet be possible. It's that I sorta cringe at having to pull all the wires from behind the tight space in back of the engine. I'll take another look when I get back to the plane. I'm at the airport at a wifi hot spot a half mile away from my hangar.



 I could also check the resistance of the spark plug wires. These came with the engine when I bought it at 50 hours. They are Champion 8.0mm(?) that I believe are shielded. It looks like there are vast differences in resistance depending on what type of wires I have. I'm not aware of the normal range for my wires, but will check them anyway. The longer wires should at least have more resistance than the shorter ones.



 If I can get to the shields of my spark plug wires, I'll test them for continuity with the inner conductor. I didn't think the shield is supposed to be connected to the condutor. A normal shielded wire doesn't have the shield carrying any current. It is grounded at one end and open at the other. But I don't see how that can be arranged with a spark plug wire. Where is the ground connection for this? In the spark plug? In the distributor cap?



 I also talked with an A&P next door about my problem. He said my NGK automotive spark plugs aren't high resistive, which means they're noisy. Suggested checking the resistance and/or replacing with aviation spark plugs. Might this possibly be a solution to my problem?



 Antenna System



 I've read the antenna system could be at fault if the noise increases when the volume control is increased. I'm not sure if I understand that. Isn't the volume control just effecting the gain of all signals, ignition noise or otherwise?



 The radio has a shielded antenna cable from the belly mount to the back of the radio. If it fits, I might be able to put a ferrite bead over the end of the antenna cable. Or over the wires going from the radio to the headset jack on the panel.



 Any help would be appreciated!



 --------

 Dan



Which motor are you using (I forgot, & it didn't make it into this post)?
	




You say 'magnetos', but you also say 'automotive spark plugs'. Are these 

aircraft mags (just about all a/c mags except very old ones are made to 

use shielded wires and shielded plugs)? If so, & you're running auto 

plugs without some type of elaborate secondary shield around them, then 

shielding on the wires, if it exists,  probably isn't doing much. 

Regular automotive wires don't normally have shields. You can buy 

resistor auto plugs. You can also buy resistor wires for auto plugs 

(normally, you'd use one or the other, but not both on the same system). 

If you have non-resistor plugs, I'd check on whether you have resistor 

type wires to go with them.



If you're running a/c mags (or an old style automotive distributor), 

there's a capacitor (most call it a condenser) inside the mag next to 

the points to suppress arcing of the contacts in the points. If the 

condenser is bad, the points usually follow pretty quickly.



I think that the volume control issue is that if the noise is getting 

into the input of the radio/audio system, then varying the volume will 

vary the noise level along with the rest of your audio. If it's coming 

in on the power supply, it might remain at the same level regardless of 

volume control settings.



If you're getting minimal noise from one ignition system and lots of 

noise from another, identical system, then that's a strong indicator 

that the problem is related to the noise producer (ignition system), and 

not to a shield/filter problem on the radio/audio system.



Charlie

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Tue May 01, 2012 6:46 pm Post subject: Re: Ignition Interference

Thanks, Charlie.



The mags are from Jabiru, but I'm not sure where they get them. I'l find out more about the plug wires and exact type of NGK plugs these are. 



Does the higher resistance of the resistive plugs make them produce less RFI? They don't have shields, do they? And as for the plug wires, are they shielded, resistive, or both? 



I also have found some more info on Jabiru ignition noise suppression. I'll post my understanding of it when I'm done later.



Thanks for sharing your insight.

_________________
Dan

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Tue May 01, 2012 9:26 pm Post subject: Re: Ignition Interference

Sounds like most of the Jabiru ignition noise comes from the HT lead between the coil and distrubutor. Folks have replaced that with a shielded one and also put a couple ferrite bead clamps on each of them. I'll try just the beads for now, I think.



I still don't know the specific type of plug wires, but found that my plugs are non-resistive. I could upgrade to resistive, but will try just the beads first, since we want to go up tomorrow. I have some spare 'bushing' type beads that might slip over the cap. Otherwise I might get some from Radio Shack, I suppose for now.

_________________
Dan

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Tue May 15, 2012 9:05 pm Post subject: Re: Ignition Interference

I'm having a major problem with RFI in my Jabiru 3300 Sonex. Radio is MGL V6, just out a few months ago. Antenna is a belly mounted homemade one made from a CB antenna. It's 22" long with a single bend, mounted ~2' behind the firewall, ~2' below the com radio. Bob made the cable, RGxxx, double shielded. I get ignition noise, left mag much worse than the right.



What I've done



Replaced spark plugs with resistive type. No difference.



Disconnected the shielded P leads. No difference.



Disconnected antenna, which cutout all noise. So I figure the noise is radiated, not conducted. I think I had the squelch all the way down, but it's possible it was turned up a little. 



Connected a separate battery. No difference.



Put beads on coil to distributor leads, antenna, power and ground leads. No difference.



Left mag makes 90% of the noise. Turned off left mag and pulled right plug wires sequentially. The right mag has always made a much slower 'tick' than the left, but still couldn't isolate it this way.



Removed jacks and a switch that could have caused ground loops on the panel. No difference.



Disconnected comm antenna (on belly, 2' aft of firewall) and connected radio to ELT antenna on top tailcone ~8-10' further back. Cut down noise, but still noticeable.



Replaced left mag spark plug wires with Accel 300+ ferro spiral plug wires. No difference



Swapped distributor caps. I was in a hurry to get my pilot up in the air, so didn't listen. He said there was no difference in flight. His transmissions were very poor. The only time he was easily understood was when he throttled back on final. He later told me the left and right were both noisy. Changing the distributor caps didn't seem to do anything. They also looked fine on the inside. 



Things I may try

 

With the new plug wires in, connect the radio to the ELT antenna 8' further back on the tailcone. Comm antenna is belly mounted, 2' back of the firewall. I'd done this before the plug wire upgrade and it made a significant improvement, but the noise was still very noticeable. 



Connect a handheld to the comm antenna. If the noise goes away, it's gotta be the radio, since we've already ruled out noise via system conduction.



Check the SWR. If this is reasonable to do, I'd prolly buy a meter for $50. My comm antenna is 22" long that I made from a cut down CB antenna. If it shows >3, I'd fix it or buy a real one.



I'll make sure athe alternator leads going to the voltage regulator are twisted. 



Replace the coil to distributor lead with noiseless wire. Some have had success with this, but most have tamed the noise with beads after using noiseless plug wires. I don't want to replace this stock coil lead, since I'm not sure I could make a secure connection and I'm doubtful it would do any good.



Any sugestions?

_________________
Dan

rickofudall

Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA

Posted: Wed May 16, 2012 2:31 pm Post subject: Ignition Interference

Borrow a different radio or use a handheld connected through your antenna system.



Rick Girard



On Wed, May 16, 2012 at 12:05 AM, messydeer <messydeer(at)yahoo.com (messydeer(at)yahoo.com)> wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "messydeer" <messydeer(at)yahoo.com (messydeer(at)yahoo.com)>

  

 I'm having a major problem with RFI in my Jabiru 3300 Sonex. Radio is MGL V6, just out a few months ago. Antenna is a belly mounted homemade one made from a CB antenna. It's 22" long with a single bend, mounted ~2' behind the firewall, ~2' below the com radio. Bob made the cable, RGxxx, double shielded. I get ignition noise, left mag much worse than the right.

  

 What I've done

 

 Replaced spark plugs with resistive type. No difference.

 

 Disconnected the shielded P leads. No difference.

 

 Disconnected antenna, which cutout all noise. So I figure the noise is radiated, not conducted. I think I had the squelch all the way down, but it's possible it was turned up a little.

 

 Connected a separate battery. No difference.

 

 Put beads on coil to distributor leads, antenna, power and ground leads. No difference.

 

 Left mag makes 90% of the noise. Turned off left mag and pulled right plug wires sequentially. The right mag has always made a much slower 'tick' than the left, but still couldn't isolate it this way.

 

 Removed jacks and a switch that could have caused ground loops on the panel. No difference.

 

 Disconnected comm antenna (on belly, 2' aft of firewall) and connected radio to ELT antenna on top tailcone ~8-10' further back. Cut down noise, but still noticeable.

 

 Replaced left mag spark plug wires with Accel 300+ ferro spiral plug wires. No difference

 

 Swapped distributor caps. I was in a hurry to get my pilot up in the air, so didn't listen. He said there was no difference in flight. His transmissions were very poor. The only time he was easily understood was when he throttled back on final. He later told me the left and right were both noisy. Changing the distributor caps didn't seem to do anything. They also looked fine on the inside.

  

 Things I may try

 

 With the new plug wires in, connect the radio to the ELT antenna 8' further back on the tailcone. Comm antenna is belly mounted, 2' back of the firewall. I'd done this before the plug wire upgrade and it made a significant improvement, but the noise was still very noticeable.

  

 Connect a handheld to the comm antenna. If the noise goes away, it's gotta be the radio, since we've already ruled out noise via system conduction.

 

 Check the SWR. If this is reasonable to do, I'd prolly buy a meter for $50. My comm antenna is 22" long that I made from a cut down CB antenna. If it shows >3, I'd fix it or buy a real one.

 

 I'll make sure athe alternator leads going to the voltage regulator are twisted.

 

 Replace the coil to distributor lead with noiseless wire. Some have had success with this, but most have tamed the noise with beads after using noiseless plug wires. I don't want to replace this stock coil lead, since I'm not sure I could make a secure connection and I'm doubtful it would do any good.

  

 Any sugestions?

 

 --------

 Dan

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=373137#373137

 

 

 

 

 

 

 

 ===========

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

 ===========

 http://forums.matronics.com

 ===========

 le, List Admin.

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

 ===========

 

 

 

 	




-- 

Zulu Delta

Mk IIIC

Thanks, Homer GBYM

It isn't necessary to have relatives in Kansas City in order to be unhappy.

   - Groucho Marx



 

  [quote][b]

_________________
The smallest miracle right in front of you is enough to make you happy....

harley(at)AgelessWings.co
Guest

Posted: Wed May 16, 2012 2:54 pm Post subject: Ignition Interference

I came across this on the Microaire website today...it's a bit     specific for strobe noise, but does go into other possible sources     and their elimination.  Specifically mentioning ground problems and     how they can affect the radios.  Even if you can't use it (or     already have!) it may make a good check list for others here.

     

     www.microair.com.au/admin/uploads/StrobeTroubleShooting1.pdf

     

     Harley 

     

     On 5/16/2012 6:29 PM, Richard Girard wrote:     [quote]Borrow a different radio or use a handheld connected       through your antenna system.       

       

       Rick Girard

         

         On Wed, May 16, 2012 at 12:05 AM,           messydeer <messydeer(at)yahoo.com (messydeer(at)yahoo.com)>           wrote:

            	  Quote: 	
		  -->             AeroElectric-List message posted by: "messydeer" <messydeer(at)yahoo.com (messydeer(at)yahoo.com)>

             

             I'm having a major problem with RFI in my Jabiru 3300 Sonex.             Radio is MGL V6, just out a few months ago. Antenna is a             belly mounted homemade one made from a CB antenna. It's 22"             long with a single bend, mounted ~2' behind the firewall,             ~2' below the com radio. Bob made the cable, RGxxx, double             shielded. I get ignition noise, left mag much worse than the             right.

             

             What I've done

             

             Replaced spark plugs with resistive type. No difference.

             

             Disconnected the shielded P leads. No difference.

             

             Disconnected antenna, which cutout all noise. So I figure             the noise is radiated, not conducted. I think I had the             squelch all the way down, but it's possible it was turned up             a little.

             

             Connected a separate battery. No difference.

             

             Put beads on coil to distributor leads, antenna, power and             ground leads. No difference.

             

             Left mag makes 90% of the noise. Turned off left mag and             pulled right plug wires sequentially. The right mag has             always made a much slower 'tick' than the left, but still             couldn't isolate it this way.

             

             Removed jacks and a switch that could have caused ground             loops on the panel. No difference.

             

             Disconnected comm antenna (on belly, 2' aft of firewall) and             connected radio to ELT antenna on top tailcone ~8-10'             further back. Cut down noise, but still noticeable.

             

             Replaced left mag spark plug wires with Accel 300+ ferro             spiral plug wires. No difference

             

             Swapped distributor caps. I was in a hurry to get my pilot             up in the air, so didn't listen. He said there was no             difference in flight. His transmissions were very poor. The             only time he was easily understood was when he throttled             back on final. He later told me the left and right were both             noisy. Changing the distributor caps didn't seem to do             anything. They also looked fine on the inside.

             

             Things I may try

             

             With the new plug wires in, connect the radio to the ELT             antenna 8' further back on the tailcone. Comm antenna is             belly mounted, 2' back of the firewall. I'd done this before             the plug wire upgrade and it made a significant improvement,             but the noise was still very noticeable.

             

             Connect a handheld to the comm antenna. If the noise goes             away, it's gotta be the radio, since we've already ruled out             noise via system conduction.

             

             Check the SWR. If this is reasonable to do, I'd prolly buy a             meter for $50. My comm antenna is 22" long that I made from             a cut down CB antenna. If it shows >3, I'd fix it or buy             a real one.

             

             I'll make sure athe alternator leads going to the voltage             regulator are twisted.

             

             Replace the coil to distributor lead with noiseless wire.             Some have had success with this, but most have tamed the             noise with beads after using noiseless plug wires. I don't             want to replace this stock coil lead, since I'm not sure I             could make a secure connection and I'm doubtful it would do             any good.

             

             Any sugestions?

             

             --------

             Dan

             

             

             

             

             Read this topic online here:

             

             http://forums.matronics.com/viewtopic.php?p=373137#373137

             

             

             

             

             

             

             

             ===========

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

             ===========

             http://forums.matronics.com

             ===========

             le, List Admin.

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

             ===========

             

             

             

           	
         

         

                  

         

         -- 

         Zulu Delta

         Mk IIIC

         Thanks, Homer GBYM

         

         

         It               isn't necessary to have relatives in Kansas City in order               to be unhappy.

                 - Groucho Marx

         

           

         

       

        	  Quote: 	
		  

	
       

No virus         found in this message.

         Checked by AVG - www.avg.com

         05/16/12     [b]

john.maccallum(at)bigpond
Guest

Posted: Wed May 16, 2012 4:26 pm Post subject: Ignition Interference

Yes the Noise may be being radiated. However it shouldn’t affect transmission. If there is a problem with both Transmit and receive then look to the

Antenna and Feedline or the radio itself.

 

I think that Jabiru Engines use Honda Lawn Mover Magnetos and Points. Check or change the Suppression Capacitors on the Points. As you have already

Replaced the Plug Leads that’s about all you can do other than check the Grounding of the Engine to the rest of the Airframe.

 

By the way doing a quick check of a Qtr Wavelength at 120 MHz I get .

 

300/120=2.5

2.5/4=.625m

 

625mm/25.4=24.6 Inches

 

24.6*0.97=23.87 Inches.

 

127.5 MHz = 22.46 Inches

 

Bending he Antenna towards the ground plane (fuselage) will affect the both the Feed point Impedance and the Resonant frequency. So

Get an SWR meter and have look at the SWR over the entire range. 118 to 137 Mhz 

 

Cheers

 

John MAcCallum

RV10 Builder #41016

VH-DUU

 

 

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Harley

Sent: Thursday, 17 May 2012 8:53 AM

To: aeroelectric-list(at)matronics.com

Subject: Re: Re: Ignition Interference

 

I came across this on the Microaire website today...it's a bit specific for strobe noise, but does go into other possible sources and their elimination.  Specifically mentioning ground problems and how they can affect the radios.  Even if you can't use it (or already have!) it may make a good check list for others here.



www.microair.com.au/admin/uploads/StrobeTroubleShooting1.pdf



Harley 

On 5/16/2012 6:29 PM, Richard Girard wrote: 

Borrow a different radio or use a handheld connected through your antenna system. 

 



Rick Girard

On Wed, May 16, 2012 at 12:05 AM, messydeer <messydeer(at)yahoo.com (messydeer(at)yahoo.com)> wrote:

--> AeroElectric-List message posted by: "messydeer" <messydeer(at)yahoo.com (messydeer(at)yahoo.com)>



I'm having a major problem with RFI in my Jabiru 3300 Sonex. Radio is MGL V6, just out a few months ago. Antenna is a belly mounted homemade one made from a CB antenna. It's 22" long with a single bend, mounted ~2' behind the firewall, ~2' below the com radio. Bob made the cable, RGxxx, double shielded. I get ignition noise, left mag much worse than the right.



What I've done



Replaced spark plugs with resistive type. No difference.



Disconnected the shielded P leads. No difference.



Disconnected antenna, which cutout all noise. So I figure the noise is radiated, not conducted. I think I had the squelch all the way down, but it's possible it was turned up a little.



Connected a separate battery. No difference.



Put beads on coil to distributor leads, antenna, power and ground leads. No difference.



Left mag makes 90% of the noise. Turned off left mag and pulled right plug wires sequentially. The right mag has always made a much slower 'tick' than the left, but still couldn't isolate it this way.



Removed jacks and a switch that could have caused ground loops on the panel. No difference.



Disconnected comm antenna (on belly, 2' aft of firewall) and connected radio to ELT antenna on top tailcone ~8-10' further back. Cut down noise, but still noticeable.



Replaced left mag spark plug wires with Accel 300+ ferro spiral plug wires. No difference



Swapped distributor caps. I was in a hurry to get my pilot up in the air, so didn't listen. He said there was no difference in flight. His transmissions were very poor. The only time he was easily understood was when he throttled back on final. He later told me the left and right were both noisy. Changing the distributor caps didn't seem to do anything. They also looked fine on the inside.



Things I may try



With the new plug wires in, connect the radio to the ELT antenna 8' further back on the tailcone. Comm antenna is belly mounted, 2' back of the firewall. I'd done this before the plug wire upgrade and it made a significant improvement, but the noise was still very noticeable.



Connect a handheld to the comm antenna. If the noise goes away, it's gotta be the radio, since we've already ruled out noise via system conduction.



Check the SWR. If this is reasonable to do, I'd prolly buy a meter for $50. My comm antenna is 22" long that I made from a cut down CB antenna. If it shows >3, I'd fix it or buy a real one.



I'll make sure athe alternator leads going to the voltage regulator are twisted.



Replace the coil to distributor lead with noiseless wire. Some have had success with this, but most have tamed the noise with beads after using noiseless plug wires. I don't want to replace this stock coil lead, since I'm not sure I could make a secure connection and I'm doubtful it would do any good.



Any sugestions?



--------

Dan





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=373137#373137



===========

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

===========

http://forums.matronics.com

===========

le, List Admin.

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

===========

 



-- 

Zulu Delta



Mk IIIC



Thanks, Homer GBYM



 



It isn't necessary to have relatives in Kansas City in order to be unhappy.

  - Groucho Marx



 



 

 	  Quote: 	
		     	


No virus found in this message.

Checked by AVG - www.avg.com

05/16/12 	  Quote: 	
		     	
0 	  Quote: 	
		   	
1 	  Quote: 	
		   	
2 	  Quote: 	
		   	
3 	  Quote: 	
		   	
4 	  Quote: 	
		   	
5 	  Quote: 	
		   	
6 	  Quote: 	
		   	
7 	  Quote: 	
		   	
8 	  Quote: 	
		   	
9 	  Quote: 	
		   	
0

  [quote][b]

skywagon

Joined: 11 Feb 2006
Posts: 184

Posted: Wed May 16, 2012 7:09 pm Post subject: Ignition Interference

..joining this thread late...

 I assume that you have a large, well  connected ground cable from the engine case to the aircraft  frame...??

 D

   

 [quote]   ---

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Wed May 16, 2012 9:06 pm Post subject: Re: Ignition Interference

 	  Quote: 	
		  you have a large, well connected ground cable 	
 Yes



 	  Quote: 	
		  . If there is a problem with both Transmit and receive then look to the 

Antenna and Feedline or the radio itself. 	
 Seems reasonable. A hangar neighbor dropped off his SWR meter. I'll get an adapter and check things tomorrow.



Thanks!

_________________
Dan

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Thu May 17, 2012 5:46 pm Post subject: Re: Ignition Interference

My SWR's all came in less than 2.1, thank Gawd! But wait, there's more. Here's what I posted on the MGL forum:



While trying to sort out my ignition noise issues, I had some odd things happen with my V6. 



To isolate everything I could, the only wires connected to the V6 are the 4 audio jacks (which are for sure isolated from the panel), the ground (goes directly to the negative of a separate battery ), the supply (separate battery), and the antenna on top of the tailcone. 



The V6 is located in the middle of my Sonex panel, ~2' off the floor, 2' behind the firewall. I turn it on and get good reception. Start the engine and the reception vanishes. I can't even get the blasted ignition noise. Rebooting the V6 with the engine running doesn't do anything. Kill the engine and there's still no reception. Adjusting the squelch does nothing. And this is with the engine turned off after having run for a minute. The only thing that lets the V6 get reception again is to reboot it AFTER the engine is off. 



The antenna, when installed, did not have a ground fault. When a handheld is swapped out for the V6, it does just fine. Even if the antenna had a ground fault to the airframe, could that cause the V6 to lose reception? There's no ground route back to the V6. If so, then why doesn't the handheld behave the same way when it is connected to the same antenna? It works just fine with the same cable and antenna. 



Next time I'm at the airport, I'll connect a portable antenna to make sure there's no ground problem. Any other suggestions?

_________________
Dan

rickofudall

Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA

Posted: Fri May 18, 2012 5:58 am Post subject: Ignition Interference

If " When a handheld is swapped out for the V6, it does just fine" means that it doesn't repeat any of the faults of the MGL radio, get an RA number and send the MGL back to the manufacturer to have it fixed or replaced. 



Rick Girard



On Thu, May 17, 2012 at 8:46 PM, messydeer <messydeer(at)yahoo.com (messydeer(at)yahoo.com)> wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "messydeer" <messydeer(at)yahoo.com (messydeer(at)yahoo.com)>

  

 My SWR's all came in less than 2.1, thank Gawd! But wait, there's more. Here's what I posted on the MGL forum:

 

 While trying to sort out my ignition noise issues, I had some odd things happen with my V6.

 

 To isolate everything I could, the only wires connected to the V6 are the 4 audio jacks (which are for sure isolated from the panel), the ground (goes directly to the negative of a separate battery ), the supply (separate battery), and the antenna on top of the tailcone.

  

 The V6 is located in the middle of my Sonex panel, ~2' off the floor, 2' behind the firewall. I turn it on and get good reception. Start the engine and the reception vanishes. I can't even get the blasted ignition noise. Rebooting the V6 with the engine running doesn't do anything. Kill the engine and there's still no reception. Adjusting the squelch does nothing. And this is with the engine turned off after having run for a minute. The only thing that lets the V6 get reception again is to reboot it AFTER the engine is off.

  

 The antenna, when installed, did not have a ground fault. When a handheld is swapped out for the V6, it does just fine. Even if the antenna had a ground fault to the airframe, could that cause the V6 to lose reception? There's no ground route back to the V6. If so, then why doesn't the handheld behave the same way when it is connected to the same antenna? It works just fine with the same cable and antenna.

  

 Next time I'm at the airport, I'll connect a portable antenna to make sure there's no ground problem. Any other suggestions?

 

 --------

 Dan

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=373257#373257

 

 

 

 

 

 

 

 ===========

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

 ===========

 http://forums.matronics.com

 ===========

 le, List Admin.

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

 ===========

 

 

 

 	




-- 

Zulu Delta

Mk IIIC

Thanks, Homer GBYM

It isn't necessary to have relatives in Kansas City in order to be unhappy.

   - Groucho Marx



 

  [quote][b]

_________________
The smallest miracle right in front of you is enough to make you happy....

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