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Radio Static Help

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ScooterF15

Joined: 19 Jun 2006
Posts: 136

Posted: Mon Oct 29, 2007 12:33 pm Post subject: Radio Static Help

Hi,



I've been on the RV-10 list for a few years, but I've never posted to AeroElectric. I've searched the list and haven't found anything that helped to solve my problem. I'd appreciate any suggestions that you can offer: 



I've spent the last few weeks trying to track down a problem with radio static on my Garmin SL-30 Nav/Comm in my Vans RV-10. The SL-30 is attached to a Garmin GMA-340 Audio panel. The static itself sounds random (i.e. not obviously uniform like I would expect from an ignition system), however, it is somehow associated with engine throttle setting. The static starts around 2000 RPM and gets progressively worse as throttle increases. On takeoff, it is so bad you can not comprehend any received transmissions. During cruise it appears to be somehow associated with manifold pressure (i.e. throttle setting, not RPM). It makes listening to ATC difficult to impossible. I also think it may be affecting my radio transmissions as well, because when I have a hard time comprehending ATC, they also have a hard time understanding me. This static appears to be only affecting the Comm audio, there is no static on NAV audio reception. I have a belly mounted bent whip VHF antenna and a wingtip VOR antenna. My handheld ICOM VHF radio does not have any static when used inside the cockpit. Also, I have a Lycoming IO-540 with one mag and one LightSpeed Plasma II+ ignition.

 

I have searched various lists for ideas and tried to solve this problem, but I have had no success in changing it at all (for better or worse). Any  suggestions for what to try or where to look will be welcome. Below is a list of some things I have tried with no luck.

 

 

General 

-Shut off all avionics (except SL-30) and both ignition systems (not both at the same time)

    --So it doesn't appear to be interference from other electronics

 

Antenna/Coaxial cable

-Added ferrite signal filters at various locations along comm coax.

-Connected SL-30 to a different comm antenna using a piece of RG-400 (tried

various routings to antennas)

-Connected SL-30 Comm to VOR antenna (great reception, still static)

    --So it doesn't appear to be antenna related

 

Power/ground

-Ensured engine grounding cables have good contacts on both ends

-Apparently new Slick Magnetos have internal suppression and do not need a filter 

-Separated SL-30 power/ground leads from bundle to reduce potential interference from other wires

-Ran SL-30 +12V and ground leads directly to battery 

-Disconnected serial connection between my SL-30 and EFIS indicator

-Connected SL-30 to separate 12V battery sitting on floor of aircraft, disconnected power/ground to GMA-340. Attached ICOM handheld antenna directly to unit (SL-30 completely isolated from aircraft)-reception still has static

-Ran ground wire from battery to SL-30 tray

-Checked to ensure headseat jacks were isolated from aircraft ground.

-Checked the shield connections for tachometer and fuel flow sensor wires

 

 

I can't think of anything else to try. Again, I'd be happy to hear any suggestions.

 

Thanks.

 

-Jim

N312JE

 

Jim "Scooter" McGrew

http://www.mit.edu/~jsmcgrew

frank.hinde(at)hp.com
Guest

Posted: Mon Oct 29, 2007 2:08 pm Post subject: Radio Static Help

Has it always been there or did it come about after a few hours running?



Sometimes I get ignition noise...Then I change out the auto plugs and it

goes away.



If you have auto plugs on your EI it might be worth a try for a $1.20 a

piece...then turn off your mag in flight.



frank 



--

mprather(at)spro.net
Guest

Posted: Mon Oct 29, 2007 2:10 pm Post subject: Radio Static Help

Based on the symptoms you have described, it sounds kind of like acoustic

noise getting into the intercom.  Have you unplugged all of the headset

mics (the small plug) from the system while in flight?

Regards,



Matt-



 	  Quote: 	
		   



 Hi,



 I've been on the RV-10 list for a few years, but I've never posted to

AeroElectric. I've searched the list and haven't found anything that
	


helped to solve my problem. I'd appreciate any suggestions that you can

offer:

 	  Quote: 	
		  

 I've spent the last few weeks trying to track down a problem with radio

static on my Garmin SL-30 Nav/Comm in my Vans RV-10. The SL-30 is
	


attached

 	  Quote: 	
		   to a Garmin GMA-340 Audio panel. The static itself sounds random (i.e.

not
	


 	  Quote: 	
		   obviously uniform like I would expect from an ignition system), however,

it is somehow associated with engine throttle setting. The static starts
	


around 2000 RPM and gets progressively worse as throttle increases. On

takeoff, it is so bad you can not comprehend any received transmissions.

During cruise it appears to be somehow associated with manifold pressure

(i.e. throttle setting, not RPM). It makes listening to ATC difficult to

impossible. I also think it may be affecting my radio transmissions as

well, because when I have a hard time comprehending ATC, they also have

a

 	  Quote: 	
		   hard time understanding me. This static appears to be only affecting the

Comm audio, there is no static on NAV audio reception. I have a belly
	


mounted bent whip VHF antenna and a wingtip!

 	  Quote: 	
		     VOR antenna. My handheld ICOM VHF radio does not have any static when

 used inside the cockpit. Also, I have a Lycoming IO-540 with one mag and

one LightSpeed Plasma II+ ignition.
	


 	  Quote: 	
		  

 I have searched various lists for ideas and tried to solve this problem,

but I have had no success in changing it at all (for better or worse).
	


Any

 	  Quote: 	
		    suggestions for what to try or where to look will be welcome. Below is

a
	


 	  Quote: 	
		   list of some things I have tried with no luck.

 General

 -Shut off all avionics (except SL-30) and both ignition systems (not

both
	


 	  Quote: 	
		   at the same time)

     --So it doesn't appear to be interference from other electronics



 Antenna/Coaxial cable

 -Added ferrite signal filters at various locations along comm coax.

-Connected SL-30 to a different comm antenna using a piece of RG-400
	


(tried

 	  Quote: 	
		   various routings to antennas)

 -Connected SL-30 Comm to VOR antenna (great reception, still static)

     --So it doesn't appear to be antenna related



 Power/ground

 -Ensured engine grounding cables have good contacts on both ends

-Apparently new Slick Magnetos have internal suppression and do not need
	


a

 	  Quote: 	
		   filter

 -Separated SL-30 power/ground leads from bundle to reduce potential

interference from other wires
	


 	  Quote: 	
		   -Ran SL-30 +12V and ground leads directly to battery

 -Disconnected serial connection between my SL-30 and EFIS indicator

-Connected SL-30 to separate 12V battery sitting on floor of aircraft,
	


disconnected power/ground to GMA-340. Attached ICOM handheld antenna

directly to unit (SL-30 completely isolated from aircraft)-reception

still

 	  Quote: 	
		   has static

 -Ran ground wire from battery to SL-30 tray

 -Checked to ensure headseat jacks were isolated from aircraft ground.

-Checked the shield connections for tachometer and fuel flow sensor
	


wires

 	  Quote: 	
		  



 I can't think of anything else to try. Again, I'd be happy to hear any

suggestions.
	


 	  Quote: 	
		  

 Thanks.



 -Jim

 N312JE



 Jim "Scooter" McGrew

 http://www.mit.edu/~jsmcgrew





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=142588#142588

ScooterF15

Joined: 19 Jun 2006
Posts: 136

Posted: Mon Oct 29, 2007 2:18 pm Post subject: Radio Static Help

Frank,

  

 I've only been flying for a year. It seems like the problem has grown worse  in the last 6 months. I just did an annual an changed out all my plugs (auto on  top / aviation on bottom).

  

 Thanks.

  

 Jim

  

 In a message dated 10/29/2007 6:10:14 P.M. Eastern Daylight Time,  frank.hinde(at)hp.com writes:

  	  Quote: 	
		  -->    AeroElectric-List message posted by: "Hinde, Frank George (Corvallis)"    <frank.hinde(at)hp.com>



Has it always been there or did it come    about after a few hours running?



Sometimes I get ignition noise...Then    I change out the auto plugs and it

goes away.



If you have auto plugs    on your EI it might be worth a try for a $1.20 a

piece...then turn off your    mag in flight.



frank 

	


 



  

 Jim "Scooter"  McGrew

http://www.mit.edu/~jsmcgrew



See what's new at AOL.com and

ScooterF15

Joined: 19 Jun 2006
Posts: 136

Posted: Mon Oct 29, 2007 2:21 pm Post subject: Radio Static Help

Yes, the intercom is completely clear when in flight with and without the  other 3 headsets plugged in. For most of the testing I turned my GMA-340 off so  the pilot's headset is wired directly to the SL-30 and the intercom is not  operating - this does not effect the static.

  

 Thanks.

  

 -Jim

  

 In a message dated 10/29/2007 6:12:07 P.M. Eastern Daylight Time,  mprather(at)spro.net writes:

  	  Quote: 	
		  -->    AeroElectric-List message posted by: "Matt Prather"    <mprather(at)spro.net>



Based on the symptoms you have described, it    sounds kind of like acoustic

noise getting into the intercom.  Have    you unplugged all of the headset

mics (the small plug) from the system    while in flight?

Regards,



Matt-

	


 



  

 Jim "Scooter"  McGrew

http://www.mit.edu/~jsmcgrew



See what's new at AOL.com and

jetboy

Joined: 22 Jul 2006
Posts: 233

Posted: Mon Oct 29, 2007 10:33 pm Post subject: Re: Radio Static Help

Have you considered the alternator regulator starting to regulate at 2000 rpm upwards, and the more pronounced effect this could be having with an older battery, letting transient noise into the DC bus?



Ralph

_________________
Ralph - CH701 / 2200a

bakerocb

Joined: 15 Jan 2006
Posts: 727
Location: FAIRFAX VA

Posted: Tue Oct 30, 2007 4:20 am Post subject: Radio Static Help

10/30/2007



Hello Scooter, You wrote: "I can't think of anything else to try. Again, I'd 

be happy to hear any suggestions."



Try going to the System mode and play around with the squelch adjustments.



Please let us know how you finally solve this problem.



'OC' Says: "The best investment we can make is the effort to gather and 

understand knowledge."



------------------------------------------------------------



Time: 01:34:50 PM PST US

Subject: Radio Static Help

From: "ScooterF15" <jsmcgrew(at)aol.com>

Hi,



I've been on the RV-10 list for a few years, but I've never posted to 

AeroElectric.

I've searched the list and haven't found anything that helped to solve my

problem. I'd appreciate any suggestions that you can offer:



--------- BIG SKIP -----------------------------------



I can't think of anything else to try. Again, I'd be happy to hear any 

suggestions.



Thanks.



-Jim

N312JE



Jim "Scooter" McGrew

http://www.mit.edu/~jsmcgrew

ScooterF15

Joined: 19 Jun 2006
Posts: 136

Posted: Tue Oct 30, 2007 5:03 am Post subject: Radio Static Help

I have an alternator over voltage protection setup with an alternator  solenoid which will open when the alternator field circuit breaker pops. I  think I've ruled out a regulator problem since the static continues after I pull  the alt field c/b; is that a bad assumption?

  

 -Jim

  

 In a message dated 10/30/2007 2:41:35 A.M. Eastern Daylight Time,  sanson.r(at)xtra.co.nz writes:

  	  Quote: 	
		  -->    AeroElectric-List message posted by: "jetboy"    <sanson.r(at)xtra.co.nz>



Have you considered the alternator    regulator starting to regulate at 2000 rpm upwards, and the more pronounced    effect this could be having with an older battery, letting transient noise    into the DC bus?



Ralph



--------

Ralph - CH701 /  2200a 	


 



  

 Jim "Scooter"  McGrew

http://www.mit.edu/~jsmcgrew  



See what's new at ww.aol.com?NCID=AOLCMP00300000001170" target="_blank">AOL.com and

bobf(at)feldtman.com
Guest

Posted: Tue Oct 30, 2007 7:35 am Post subject: Radio Static Help

I'd check spark plug wires.

  

 need ones with considerable inductance (spiral wound) to surpress HV RFI

  

 bobf



 

 On 10/30/07, JSMcGrew(at)aol.com (JSMcGrew(at)aol.com) <JSMcGrew(at)aol.com (JSMcGrew(at)aol.com)> wrote: [quote]    I have an alternator over voltage protection setup with an alternator solenoid which will open when the alternator field circuit breaker pops. I think I've ruled out a regulator problem since the static continues after I pull the alt field c/b; is that a bad assumption? 

  

 -Jim

  

 In a message dated 10/30/2007 2:41:35 A.M. Eastern Daylight Time, sanson.r(at)xtra.co.nz (sanson.r(at)xtra.co.nz) writes:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "jetboy" < sanson.r(at)xtra.co.nz (sanson.r(at)xtra.co.nz)>



Have you considered the alternator regulator starting to regulate at 2000 rpm upwards, and the more pronounced effect this could be having with an older battery, letting transient noise into the DC bus? 



Ralph



--------

Ralph - CH701 / 2200a 	


 



  

 Jim "Scooter" McGrew

http://www.mit.edu/~jsmcgrew  



   See what's new at ww.aol.com?NCID=AOLCMP00300000001170" target="_blank"> 



[b]

f.miskelly(at)imperial.ac
Guest

Posted: Tue Oct 30, 2007 8:33 am Post subject: Radio Static Help

I had an exactly identical problem with a KX155. There was a thread on it several months ago

Eventually found it was the intercom picking up ignition noise. To diagnose it i had to remove the intercom pin from the back of the radio. Most, but not all, of the noise disappeared. Just working on one headset without removing the intercom pin-out still gave the problem. Solved it by installing an external intercom.

  -  Frank



________________________________



From: owner-aeroelectric-list-server(at)matronics.com on behalf of Matt Prather

Sent: Mon 29/10/2007 22:09

To: aeroelectric-list(at)matronics.com

Subject: Re: Radio Static Help






Based on the symptoms you have described, it sounds kind of like acoustic

noise getting into the intercom.  Have you unplugged all of the headset

mics (the small plug) from the system while in flight?

Regards,



Matt-



 	  Quote: 	
		   



 Hi,



 I've been on the RV-10 list for a few years, but I've never posted to

AeroElectric. I've searched the list and haven't found anything that
	


helped to solve my problem. I'd appreciate any suggestions that you can

offer:

 	  Quote: 	
		  

 I've spent the last few weeks trying to track down a problem with radio

static on my Garmin SL-30 Nav/Comm in my Vans RV-10. The SL-30 is
	


attached

 	  Quote: 	
		   to a Garmin GMA-340 Audio panel. The static itself sounds random (i.e.

not
	


 	  Quote: 	
		   obviously uniform like I would expect from an ignition system), however,

it is somehow associated with engine throttle setting. The static starts
	


around 2000 RPM and gets progressively worse as throttle increases. On

takeoff, it is so bad you can not comprehend any received transmissions.

During cruise it appears to be somehow associated with manifold pressure

(i.e. throttle setting, not RPM). It makes listening to ATC difficult to

impossible. I also think it may be affecting my radio transmissions as

well, because when I have a hard time comprehending ATC, they also have

a

 	  Quote: 	
		   hard time understanding me. This static appears to be only affecting the

Comm audio, there is no static on NAV audio reception. I have a belly
	


mounted bent whip VHF antenna and a wingtip!

 	  Quote: 	
		     VOR antenna. My handheld ICOM VHF radio does not have any static when

 used inside the cockpit. Also, I have a Lycoming IO-540 with one mag and

one LightSpeed Plasma II+ ignition.
	


 	  Quote: 	
		  

 I have searched various lists for ideas and tried to solve this problem,

but I have had no success in changing it at all (for better or worse).
	


Any

 	  Quote: 	
		    suggestions for what to try or where to look will be welcome. Below is

a
	


 	  Quote: 	
		   list of some things I have tried with no luck.

 General

 -Shut off all avionics (except SL-30) and both ignition systems (not

both
	


 	  Quote: 	
		   at the same time)

     --So it doesn't appear to be interference from other electronics



 Antenna/Coaxial cable

 -Added ferrite signal filters at various locations along comm coax.

-Connected SL-30 to a different comm antenna using a piece of RG-400
	


(tried

 	  Quote: 	
		   various routings to antennas)

 -Connected SL-30 Comm to VOR antenna (great reception, still static)

     --So it doesn't appear to be antenna related



 Power/ground

 -Ensured engine grounding cables have good contacts on both ends

-Apparently new Slick Magnetos have internal suppression and do not need
	


a

 	  Quote: 	
		   filter

 -Separated SL-30 power/ground leads from bundle to reduce potential

interference from other wires
	


 	  Quote: 	
		   -Ran SL-30 +12V and ground leads directly to battery

 -Disconnected serial connection between my SL-30 and EFIS indicator

-Connected SL-30 to separate 12V battery sitting on floor of aircraft,
	


disconnected power/ground to GMA-340. Attached ICOM handheld antenna

directly to unit (SL-30 completely isolated from aircraft)-reception

still

 	  Quote: 	
		   has static

 -Ran ground wire from battery to SL-30 tray

 -Checked to ensure headseat jacks were isolated from aircraft ground.

-Checked the shield connections for tachometer and fuel flow sensor
	


wires

 	  Quote: 	
		  



 I can't think of anything else to try. Again, I'd be happy to hear any

suggestions.
	


 	  Quote: 	
		  

 Thanks.



 -Jim

 N312JE



 Jim "Scooter" McGrew

 http://www.mit.edu/~jsmcgrew





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=142588#142588

xl(at)prosody.org
Guest

Posted: Tue Oct 30, 2007 9:59 pm Post subject: Radio Static Help

I had a similar problem. static on takeoff and > ~2000 rpm

and loader as RPM increased.

I found a bad crimp connection on an alternator wire.

The wires were oxidized - not a gas tight connection.

I soldered the connection and it's been quiet since.

Some frequencies did not have static. 123.05 did.

Hence the randomness.



I also had static, at one time, from loose distributor caps.



Joe E (at) BFI

N633Z ~495 hours

CH601XL, Jabiru 3300A

On Mon, 29 Oct 2007, ScooterF15 wrote:

 	  Quote: 	
		   

 Hi,

 I've been on the RV-10 list for a few years, but I've never posted to

 AeroElectric. I've searched the list and haven't found anything that

 helped to solve my problem. I'd appreciate any suggestions that you can

 offer:

 I've spent the last few weeks trying to track down a problem with radio

 static on my Garmin SL-30 Nav/Comm in my Vans RV-10. The SL-30 is

 attached to a Garmin GMA-340 Audio panel. The static itself sounds

 random (i.e. not obviously uniform like I would expect from an ignition

 system), however, it is somehow associated with engine throttle setting.

 The static starts around 2000 RPM and gets progressively worse as

 throttle increases. On takeoff, it is so bad you can not comprehend any

 received transmissions. During cruise it appears to be somehow

 associated with manifold pressure (i.e. throttle setting, not RPM). It

 makes listening to ATC difficult to impossible. I also think it may be

 affecting my radio transmissions as well, because when I have a hard

 time comprehending ATC, they also have a hard time understanding me.

 .......snip .......snip

 do not archive

donaldjsmith(at)ukonline.
Guest

Posted: Wed Oct 31, 2007 2:16 pm Post subject: Radio Static Help

Have you consider the HT  leads to the plugs - say breakdown of insulation/suppression.  Use to get  this sort of fault in the old days on cars.  Might be temp. related.   Suggest replacing all HT side of ignition system.

  

 Donald

 [quote]   ---

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