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rossmickey(at)comcast.net
Guest

Posted: Thu Jul 16, 2015 7:58 am Post subject: Radio Buzz

I know that asking about the cause of a buzz in your radios is like asking a mechanic about a noise you hear when you are driving but since you are all here and know way more than me I will describe my situation and how I plan to proceed.

 

Set-up

RV-6A

GX-60 Com

SL-30 Com

SL-15 Intercom

Two COMANT VHF COMMUNICATIONS antenna mounted on the centerline of the belly (one below the seat, one below the baggage compartment)

 

I am getting significant static like noise when I connect either radio to the front antenna.  I have switched the antennas with no change. The front antenna connection goes pretty much straight down to the floor with a short male-male piece of coax (which I have changed with no result) to connect the female ends of the antenna and radio coax.  The antenna wire crosses a bunch of wires at a 90 degree angle and goes right next to where I have a temporary battery placed.

 

My conclusions:

The radios, antennas and cables are all ok so I must be picking up interference from either the wires or the battery.

 

Solution:

Move the battery and see if it helps (I would have last night but ran out of time)

 

What do you think?

 

Also, I get a very slight hum when I put my hand near (1 inch away) or touch the SL-30.  It doesn’t bother me but I find it interesting that I just have to get near the radio for the noise to happen.

 

Thanks all,

 

Ross Mickey

N9PT

RV-6A

  [quote][b]

rossmickey(at)comcast.net
Guest

Posted: Thu Jul 16, 2015 2:20 pm Post subject: Radio Buzz

More info…

 

My plane is not in a state that allows me to start the engine (wings are off) so this is occurring with just the master switch on.  No strobes or landing lights on, just panel instruments on.  The main change since I last used the radios is the installation of a Advanced Flight System 5600 EFIS but the only wiring from that which are near my antenna cable are the GPS, Comm Radio and Autopilot serial/ARINC wires.

 

Ross

 

 

From: Ross Home [mailto:rossmickey(at)comcast.net] 

Sent: Thursday, July 16, 2015 8:57 AM

To: 'aeroelectric-list(at)matronics.com'

Subject: Radio Buzz

 

I know that asking about the cause of a buzz in your radios is like asking a mechanic about a noise you hear when you are driving but since you are all here and know way more than me I will describe my situation and how I plan to proceed.

 

Set-up

RV-6A

GX-60 Com

SL-30 Com

SL-15 Intercom

Two COMANT VHF COMMUNICATIONS antenna mounted on the centerline of the belly (one below the seat, one below the baggage compartment)

 

I am getting significant static like noise when I connect either radio to the front antenna.  I have switched the antennas with no change. The front antenna connection goes pretty much straight down to the floor with a short male-male piece of coax (which I have changed with no result) to connect the female ends of the antenna and radio coax.  The antenna wire crosses a bunch of wires at a 90 degree angle and goes right next to where I have a temporary battery placed.

 

My conclusions:

The radios, antennas and cables are all ok so I must be picking up interference from either the wires or the battery.

 

Solution:

Move the battery and see if it helps (I would have last night but ran out of time)

 

What do you think?

 

Also, I get a very slight hum when I put my hand near (1 inch away) or touch the SL-30.  It doesn’t bother me but I find it interesting that I just have to get near the radio for the noise to happen.

 

Thanks all,

 

Ross Mickey

N9PT

RV-6A

  [quote][b]

user9253

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

Posted: Thu Jul 16, 2015 2:53 pm Post subject: Re: Radio Buzz

Is the temporary battery powering the avionics?  Is the negative battery terminal grounded to the airframe?

  Turn everything on, then measure the voltage between the negative battery terminal and the radio case.  How many millivolts?

Joe

_________________
Joe Gores

n1deltawhiskey(at)comcast
Guest

Posted: Thu Jul 16, 2015 3:43 pm Post subject: Radio Buzz

Ross,

 

What you are picking up is probably some sort of RFI or EMI. I doubt it will be coming from your battery unless you have some grounding issues, and may not even be coming from your wires. 

 

That leaves the noise generators which includes all of your other avionics and electrical devices and systems including strobes, engine/ignition system, etc. And that is assuming there is no noise generated because of ground loops in your aircraft. So the process is to eliminate noise generators, one by one, assuming there is no noise in your antenna/cable/radio when tested with ALL other electrical equipment turned off. If your radio still generates noise when you put your hand near it, I would consider grounding the case.

 

Then, turn on one electrical device at a time to see if it generates any noise. With my GX-60, I noticed the Dynon D10A introduced some hum in the system when turned on. The strobe circuit also introduced some noise. Test each electrical system sequentially to find the biggest "offenders". This process will give you some idea of where to look to attempt to reduce noise in the com system.

 

I recently had my transponder checked and asked about noise in the radio system. He commented that some noise tended to "go with the territory". 

 

Not necessarily related, I queried him about very loud feedback when attempting to transmit. Turns out that a setting in the GX-60 for the microphone was set to the maximum as shipped from the factory. The point here is to also check you GX-60 setup parameters. Some adjustments there might assist in correcting your issues.

 

Doug Windhorn



 [quote][b]

kboatright1(at)comcast.ne
Guest

Posted: Thu Jul 16, 2015 4:16 pm Post subject: Radio Buzz

http://www.warbirdinformationexchange.org/phpBB3/viewtopic.php?f=3&t=52024

  From: Ross Home (rossmickey(at)comcast.net) 

 Sent: Thursday, July 16, 2015 6:19 PM

 To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)  

 Subject: RE: Radio Buzz

More  infoâ€¦ 

My plane is  not in a state that allows me to start the engine (wings are off) so this is  occurring with just the master switch on.  No strobes or landing lights on,  just panel instruments on.  The main change since I last used the radios is  the installation of a Advanced Flight System 5600 EFIS but the only wiring from  that which are near my antenna cable are the GPS, Comm Radio and Autopilot  serial/ARINC wires. 

Ross 

From: Ross Home  [mailto:rossmickey(at)comcast.net] 

Sent: Thursday, July 16, 2015 8:57  AM

To: 'aeroelectric-list(at)matronics.com'

Subject: Radio  Buzz

I know that asking  about the cause of a buzz in your radios is like asking a mechanic about a noise  you hear when you are driving but since you are all here and know way more than  me I will describe my situation and how I plan to proceed. 

Set-up 

RV-6A 

GX-60  Com 

SL-30  Com 

SL-15  Intercom 

Two COMANT VHF  COMMUNICATIONS antenna mounted on the centerline of the belly (one below the  seat, one below the baggage compartment) 

I am getting  significant static like noise when I connect either radio to the front  antenna.  I have switched the antennas with no change. The front antenna  connection goes pretty much straight down to the floor with a short male-male  piece of coax (which I have changed with no result) to connect the female ends  of the antenna and radio coax.  The antenna wire crosses a bunch of wires  at a 90 degree angle and goes right next to where I have a temporary battery  placed. 

My  conclusions: 

The radios, antennas  and cables are all ok so I must be picking up interference from either the wires  or the battery. 

Solution: 

Move the battery and  see if it helps (I would have last night but ran out of  time) 

What do you  think? 

Also, I get a very  slight hum when I put my hand near (1 inch away) or touch the SL-30.  It  doesnâ€™t bother me but I find it interesting that I just have to get near the  radio for the noise to happen. 

Thanks  all, 

Ross  Mickey 

N9PT 

RV-6A

[quote]

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href="http://forums.matronics.com">http://forums.matronics.com

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[b]

kboatright1(at)comcast.ne
Guest

Posted: Thu Jul 16, 2015 4:39 pm Post subject: Radio Buzz

Ooops, cross post.

  

 Do not archive.

    

  From: kboatright1(at)comcast.net (kboatright1(at)comcast.net) 

 Sent: Thursday, July 16, 2015 8:15 PM

 To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)  

 Subject: Re: RE: Radio Buzz

  



    http://www.warbirdinformationexchange.org/phpBB3/viewtopic.php?f=3&t=52024

    

  From: Ross Home (rossmickey(at)comcast.net) 

 Sent: Thursday, July 16, 2015 6:19 PM

 To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)  

 Subject: RE: Radio Buzz

  



   

More  infoâ€¦ 

  

My plane is  not in a state that allows me to start the engine (wings are off) so this is  occurring with just the master switch on.  No strobes or landing lights on,  just panel instruments on.  The main change since I last used the radios is  the installation of a Advanced Flight System 5600 EFIS but the only wiring from  that which are near my antenna cable are the GPS, Comm Radio and Autopilot  serial/ARINC wires. 

  

Ross 

  

    

From: Ross Home  [mailto:rossmickey(at)comcast.net] 

Sent: Thursday, July 16, 2015 8:57  AM

To: 'aeroelectric-list(at)matronics.com'

Subject: Radio  Buzz



 

  

I know that asking  about the cause of a buzz in your radios is like asking a mechanic about a noise  you hear when you are driving but since you are all here and know way more than  me I will describe my situation and how I plan to proceed. 

  

Set-up 

RV-6A 

GX-60  Com 

SL-30  Com 

SL-15  Intercom 

Two COMANT VHF  COMMUNICATIONS antenna mounted on the centerline of the belly (one below the  seat, one below the baggage compartment) 

  

I am getting  significant static like noise when I connect either radio to the front  antenna.  I have switched the antennas with no change. The front antenna  connection goes pretty much straight down to the floor with a short male-male  piece of coax (which I have changed with no result) to connect the female ends  of the antenna and radio coax.  The antenna wire crosses a bunch of wires  at a 90 degree angle and goes right next to where I have a temporary battery  placed. 

  

My  conclusions: 

The radios, antennas  and cables are all ok so I must be picking up interference from either the wires  or the battery. 

  

Solution: 

Move the battery and  see if it helps (I would have last night but ran out of  time) 

  

What do you  think? 

  

Also, I get a very  slight hum when I put my hand near (1 inch away) or touch the SL-30.  It  doesnâ€™t bother me but I find it interesting that I just have to get near the  radio for the noise to happen. 

  

Thanks  all, 

  

Ross  Mickey 

N9PT 

RV-6A

[quote]



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href="http://forums.matronics.com">http://forums.matronics.com

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





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href="http://forums.matronics.com">http://forums.matronics.com

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

[b]

deej(at)deej.net
Guest

Posted: Thu Jul 16, 2015 5:21 pm Post subject: Radio Buzz

On 7/16/2015 6:19 PM, Ross Home wrote:

 	  Quote: 	
		   My plane is not in a state that allows me to start the engine (wings are

 off) so this is occurring with just the master switch on.  No strobes or

 landing lights on, just panel instruments on. 


	




Just a random thought, but is this inside your hangar?  Is there

anything on in the hangar, like lights, a refrigerator, etc?



The noise might not be coming from anything in the plane.



-Dj



-- 

Dj Merrill - N1JOV - EAA Chapter 87

Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/

Glastar Flyer N866RH - http://deej.net/glastar/

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Thu Jul 16, 2015 9:19 pm Post subject: Radio Buzz

Excellent thought. I had squelch break of sorts on my SL30 until I 

realized it came and went with the light switch. One florescent tube was 

causing its ballast to put out  a bunch of RFI. New tube, noise gone.

On 7/16/2015 6:20 PM, Dj Merrill wrote:

 	  Quote: 	

 On 7/16/2015 6:19 PM, Ross Home wrote:

> My plane is not in a state that allows me to start the engine (wings are

> off) so this is occurring with just the master switch on.  No strobes or

> landing lights on, just panel instruments on.

 Just a random thought, but is this inside your hangar?  Is there

 anything on in the hangar, like lights, a refrigerator, etc?

 The noise might not be coming from anything in the plane.

 -Dj

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

halbenjamin101(at)gmail.c
Guest

Posted: Fri Jul 17, 2015 3:46 am Post subject: Radio Buzz

I have a handheld radio in my hanger that I listen to while doing my preflight. Battery chargers for electronic devices often cause noise.

Hal Benjamin

RV4, Long Island, NY

Sent from my iPad

 	  Quote: 	
		   On Jul 17, 2015, at 1:16 AM, Kelly McMullen <kellym(at)aviating.com> wrote:

 Excellent thought. I had squelch break of sorts on my SL30 until I realized it came and went with the light switch. One florescent tube was causing its ballast to put out  a bunch of RFI. New tube, noise gone.

> On 7/16/2015 6:20 PM, Dj Merrill wrote:

> 

> 

>> On 7/16/2015 6:19 PM, Ross Home wrote:

>> My plane is not in a state that allows me to start the engine (wings are

>> off) so this is occurring with just the master switch on.  No strobes or

>> landing lights on, just panel instruments on.

> 

> Just a random thought, but is this inside your hangar?  Is there

> anything on in the hangar, like lights, a refrigerator, etc?

> 

> The noise might not be coming from anything in the plane.

> 

> -Dj

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Jul 17, 2015 6:32 am Post subject: Radio Buzz

At 10:57 AM 7/16/2015, you wrote:

  	  Quote: 	
		  I know that asking about the cause of a buzz in your radios is like asking a mechanic about a noise you hear when you are driving but since you are all here and know way more than me I will describe my situation and how I plan to proceed.

  

 Set-up

 RV-6A

 GX-60 Com

 SL-30 Com

 SL-15 Intercom

 Two  COMANT VHF COMMUNICATIONS antenna mounted on the centerline of the belly (one below the seat, one below the baggage compartment)

  

 I am getting significant static like noise when I connect either radio to the front antenna. 	


   This sounds like a radiated noise issue which is almost

   never an issue with grounding or other installation

   errors . . . it's usually some device that is not

   designed to live in harmony on airplanes.



   Find a hand-held radio. Adjust to unused frequency

   and open the squelch so you can hear the background

   'hiss'. Then use it to 'probe' about the various

   devices on the airplane. 



   Hand-held vhf transceivers and 9v transistor am radios

   have been quite useful for probing noise sources of

   all stripe.



   Also, conduct a power-down study. Pull all fuses/breakers

   that power up the ship's accessories. If noise is gone,

   replace fuses one at a time until the noise comes back.



 

   Bob . . .    [quote][b]

rossmickey(at)comcast.net
Guest

Posted: Fri Jul 17, 2015 6:52 am Post subject: Radio Buzz

I will try this. 

 

What is puzzling is that the antenna connection that leads to the rear antenna is at the firewall about 18 inches and level with my GX-60.  I can easily unhook the GX-60 cable from the front antenna (which is under the floor directly beneath the GX-60) and hook it to the rear antenna connection which is at the same height as the GX-60 and the noise goes away.  All of the wires that the GX-60 cable passes are the same in either case except, when it is connected to the front antenna, it crosses these wires at a 90 degree angle instead of running parallel to them when it goes the rear antenna connection.

 

Like I said earlier, I switched the two antenna to see if one was bad with no change.

 

I am using a ground block for all grounding as suggested by Bob and the battery is attached to it.

 

This also occurred out of the hangar so it isn’t noise being generated outside of the airplane.

 

Thank you all 

 

Ross 

 

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Robert L. Nuckolls, III

Sent: Friday, July 17, 2015 7:30 AM

To: aeroelectric-list(at)matronics.com

Subject: Re: Radio Buzz

 

At 10:57 AM 7/16/2015, you wrote:



 	  Quote: 	
		  

I know that asking about the cause of a buzz in your radios is like asking a mechanic about a noise you hear when you are driving but since you are all here and know way more than me I will describe my situation and how I plan to proceed.

 

Set-up

RV-6A

GX-60 Com

SL-30 Com

SL-15 Intercom

Two COMANT VHF COMMUNICATIONS antenna mounted on the centerline of the belly (one below the seat, one below the baggage compartment)

 

I am getting significant static like noise when I connect either radio to the front antenna. 	




  This sounds like a radiated noise issue which is almost

  never an issue with grounding or other installation

  errors . . . it's usually some device that is not

  designed to live in harmony on airplanes.



  Find a hand-held radio. Adjust to unused frequency

  and open the squelch so you can hear the background

  'hiss'. Then use it to 'probe' about the various

  devices on the airplane. 



  Hand-held vhf transceivers and 9v transistor am radios

  have been quite useful for probing noise sources of

  all stripe.



  Also, conduct a power-down study. Pull all fuses/breakers

  that power up the ship's accessories. If noise is gone,

  replace fuses one at a time until the noise comes back.



  Bob . . .  	  Quote: 	
		    http://www.matronics.com/Navigator?AeroElectric-List 	
0 	  Quote: 	
		   	
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  [quote][b]

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Fri Jul 17, 2015 8:07 am Post subject: Radio Buzz

Since you have ruled out external sources, it sort of points to the     front antenna cable. I thought you said you had tried swapping     cables.

     Try removing antenna from airframe, connecting it directly to radio     and see if there is noise.

     I can't explain it, but I know of one case where noise was coming     via ground, and isolating the antenna from ground cured the problem.     Perhaps a ground loop between coax shield and the airframe ground.

     

     On 7/17/2015 7:51 AM, Ross Home wrote:

     

     [quote]                       <![endif]-->   <![endif]-->                

I will try this.          

          

What is puzzling is that             the antenna connection that leads to the rear antenna is at             the firewall about 18 inches and level with my GX-60.  I can             easily unhook the GX-60 cable from the front antenna (which             is under the floor directly beneath the GX-60) and hook it             to the rear antenna connection which is at the same height             as the GX-60 and the noise goes away.  All of the wires that             the GX-60 cable passes are the same in either case except,             when it is connected to the front antenna, it crosses these             wires at a 90 degree angle instead of running parallel to             them when it goes the rear antenna connection.         

          

Like I said earlier, I             switched the two antenna to see if one was bad with no             change.         

          

I am using a ground block             for all grounding as suggested by Bob and the battery is             attached to it.         

          

This also occurred out of             the hangar so it isn’t noise being generated outside of the             airplane.         

          

Thank you all          

          

Ross          

                                  

From:                 owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com)                 [mailto:owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com)] On                   Behalf Of Robert L. Nuckolls, III

                 Sent: Friday, July 17, 2015 7:30 AM

                 To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)

                 Subject: Re: Radio Buzz           

         

         

          

At 10:57 AM 7/16/2015, you wrote:

           

                     	  Quote: 	
		             

I know that asking about the cause of a             buzz in your radios is like asking a mechanic about a noise             you hear when you are driving but since you are all here and             know way more than me I will describe my situation and how I             plan to proceed.

              

             Set-up

             RV-6A

             GX-60 Com

             SL-30 Com

             SL-15 Intercom

             Two COMANT               VHF COMMUNICATIONS antenna mounted on the centerline             of the belly (one below the seat, one below the baggage             compartment)

              

             I am getting significant static like noise when I connect             either radio to the front antenna.         	
         



             This sounds like a radiated noise issue which is almost

             never an issue with grounding or other installation

             errors . . . it's usually some device that is not

             designed to live in harmony on airplanes.

           

             Find a hand-held radio. Adjust to unused frequency

             and open the squelch so you can hear the background

             'hiss'. Then use it to 'probe' about the various

             devices on the airplane. 

           

             Hand-held vhf transceivers and 9v transistor am radios

             have been quite useful for probing noise sources of

             all stripe.

           

             Also, conduct a power-down study. Pull all fuses/breakers

             that power up the ship's accessories. If noise is gone,

             replace fuses one at a time until the noise comes back.

           

           

                    

  Bob . . .           	  Quote: 	
		    http://www.matronics.com/Navigator?AeroElectric-List  	
0          	  Quote: 	
		    	
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_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

ARGOLDMAN(at)aol.com
Guest

Posted: Fri Jul 17, 2015 10:04 am Post subject: Radio Buzz

Bob's idea is probably right, but with two basically identical antennas I  would vote for a problem with the problem antenna, probably the coax-  connector-or connection to the antenna or a faulty antenna, if it is store  bought. Connect your portable to each antenna to  re re re varify that the  front antenna is indeed the one that is giving the problem. Then do a continuity  check to see if somewhere the cable has been kinked and is intermittently  shorting (move as much of it as you can around.

  

 If the noise is coming from inside of the aircraft, shutting all things off  (with the exception of the errant radio and listening would probably be a good  first test. If quiet, turn on each separate one (disconnect them via their  fuses/CBs, not just their switches.

  

 If it is coming from the hanger, merely reverse the location of the  aircraft and the problem  may go to the other antenna. A better test is to  take the beast out of the hanger and try to duplicate the problem. My vote is  the antenna or its lead/connectors, etc.

  

 By the way. communication waves are vertically polarized   your  antennas are horizontally polarized. I dont know how much of a problem this is.  That is for others to comment about

  

 Rich

  

  In a message dated 7/17/2015 9:34:07 A.M. Central Daylight Time,  nuckolls.bob(at)aeroelectric.com writes:

  	  Quote: 	
		  At 10:57 AM 7/16/2015, you wrote:

    	  Quote: 	
		  I know that asking about the      cause of a buzz in your radios is like asking a mechanic about a noise you      hear when you are driving but since you are all here and know way more than      me I will describe my situation and how I plan to      proceed.

 

Set-up

RV-6A

GX-60 Com

SL-30 Com

SL-15      Intercom

Two COMANT      VHF COMMUNICATIONS antenna mounted on the centerline of the belly (one      below the seat, one below the baggage compartment)

 

I am getting      significant static like noise when I connect either radio to the front      antenna. 	


  This sounds like a radiated noise issue    which is almost

  never an issue with grounding or other    installation

  errors . . . it's usually some device that is    not

  designed to live in harmony on airplanes.



  Find a    hand-held radio. Adjust to unused frequency

  and open the squelch so    you can hear the background

  'hiss'. Then use it to 'probe' about the    various

  devices on the airplane. 



  Hand-held vhf    transceivers and 9v transistor am radios

  have been quite useful for    probing noise sources of

  all stripe.



  Also, conduct a    power-down study. Pull all fuses/breakers

  that power up the ship's    accessories. If noise is gone,

  replace fuses one at a time until the    noise comes back.



   

  Bob . . .  	  Quote: 	
		  



====================================

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

====================================

ms.matronics.com/">http://forums.matronics.com

====================================

tp://www.matronics.com/contribution">http://www.matronics.com/contribution

====================================



	
	


 [quote][b]

ARGOLDMAN(at)aol.com
Guest

Posted: Fri Jul 17, 2015 10:05 am Post subject: Radio Buzz

I just looked up your antenna-- forget the part of polarization in the last  post..It is possible that you have an infant mortality.

  

 Rich

  

  In a message dated 7/17/2015 9:34:07 A.M. Central Daylight Time,  nuckolls.bob(at)aeroelectric.com writes:

  	  Quote: 	
		  At 10:57 AM 7/16/2015, you wrote:

    	  Quote: 	
		  I know that asking about the      cause of a buzz in your radios is like asking a mechanic about a noise you      hear when you are driving but since you are all here and know way more than      me I will describe my situation and how I plan to      proceed.

 

Set-up

RV-6A

GX-60 Com

SL-30 Com

SL-15      Intercom

Two COMANT      VHF COMMUNICATIONS antenna mounted on the centerline of the belly (one      below the seat, one below the baggage compartment)

 

I am getting      significant static like noise when I connect either radio to the front      antenna. 	


  This sounds like a radiated noise issue    which is almost

  never an issue with grounding or other    installation

  errors . . . it's usually some device that is    not

  designed to live in harmony on airplanes.



  Find a    hand-held radio. Adjust to unused frequency

  and open the squelch so    you can hear the background

  'hiss'. Then use it to 'probe' about the    various

  devices on the airplane. 



  Hand-held vhf    transceivers and 9v transistor am radios

  have been quite useful for    probing noise sources of

  all stripe.



  Also, conduct a    power-down study. Pull all fuses/breakers

  that power up the ship's    accessories. If noise is gone,

  replace fuses one at a time until the    noise comes back.



   

  Bob . . .  	  Quote: 	
		  



====================================

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

====================================

ms.matronics.com/">http://forums.matronics.com

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tp://www.matronics.com/contribution">http://www.matronics.com/contribution

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 [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Jul 17, 2015 10:46 am Post subject: Radio Buzz

At 11:05 AM 7/17/2015, you wrote:

  	  Quote: 	
		  Since you have ruled out external sources, it sort of points to the front antenna cable. I thought you said you had tried swapping cables.

 Try removing antenna from airframe, connecting it directly to radio and see if there is noise.

 I can't explain it, but I know of one case where noise was coming via ground, and isolating the antenna from ground cured the problem. Perhaps a ground loop between coax shield and the airframe ground.



 On 7/17/2015 7:51 AM, Ross Home wrote:

  	  Quote: 	
		  I will try this. 

  

 What is puzzling is that the antenna connection that leads to the rear antenna is at the firewall about 18 inches and level with my GX-60.  I can easily unhook the GX-60 cable from the front antenna (which is under the floor directly beneath the GX-60) and hook it to the rear antenna connection which is at the same height as the GX-60 and the noise goes away.  All of the wires that the GX-60 cable passes are the same in either case except, when it is connected to the front antenna, it crosses these wires at a 90 degree angle instead of running parallel to them when it goes the rear antenna connection. 	
	


   Routing of coax cables to antennas is NEVER

   a component of received noise . . . in the

   heavy iron we route coaxes where there is opportunity

   and room. The whole idea behind the industry standard

   practices for (1) limiting noise from antagonists,

   (2) improving resistance to noise by judicious

   design of potential victims and last (3) reducing

   risk of over-whelming propagation path (mounting

   an antenna under the cowl will probably pick up

   ignition noise). When a noise coming in through

   the receiver's antenna port is detected, placement

   of the coax isn't even a distant finisher in the

   quest for resolution.



   Assuming you have paid due diligence to standard practices

   for installing the two antennas then the fact that

   the forward-most antenna seems to be the key propagation

   port, then the noise source is most likely forward ON

   the aircraft. If it were off the aircraft, both

   antennas would hear it.



   This problem has a lot in common with Col_Mustard-

   did-it-in-the-library-with-a-rope . . . you gotta

   gather all the clues available to you BEFORE picking

   up hammers-n-saws . . . or screwdrivers.



   Antennas don't go BAD in a manner that makes one

   a source of noise while others are not. They either

   work good . . . or they don't . . . but they're never

   'noisy'. Start with a 'cold' panel and bring up

   equipment one item at a time . . . then confirm

   your preliminary findings with a sniffer receiver.



   Only THEN will hammers, saws and screwdrivers

   contribute to resolution of the problem.



 

   Bob . . .    [quote][b]

rossmickey(at)comcast.net
Guest

Posted: Fri Jul 17, 2015 11:45 am Post subject: Radio Buzz

Thanks so much, Bob.  I will do as you suggest when I get back out to the hangar.  

 

Just for my education.  Since the location of the coax is not an issue, am I to understand that the interference I am experiencing is being picked up by the forward antenna itself?

 

In surfing the web about comm antenna, I read about the importance of having good electrical bonding of the antenna to the aircraft ground.

 

The electrical bonding of the antennas to the aircraft skin is best accomplished by direct metal-to metal contact of the antenna base to the aircraft skin. To accomplish this, the aircraft paint in the mounting area will need to be removed and the surface alodined to protect aluminum against corrosion. An alternate method for providing electrical bonding is through the mounting screws, which attach to a backing plate inside the aircraft skin. Remove any interior paint in the area where the backing plate is placed to assure a good ground. Coat this area with alodine to minimize corrosion. To test the electrical bonding of the blade to the aircraft, a reading of .003 ohms between the antenna base plate and ground should be achieved.

 

I am using the second method and will have to check if my installation meets the .003 ohm test.  If the front antenna does not meet this, would this cause a buzz or just degrade the performance of the antenna?

 

Ross

 

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Robert L. Nuckolls, III

Sent: Friday, July 17, 2015 11:45 AM

To: aeroelectric-list(at)matronics.com

Subject: Re: Radio Buzz

 

At 11:05 AM 7/17/2015, you wrote:



 	  Quote: 	
		  

Since you have ruled out external sources, it sort of points to the front antenna cable. I thought you said you had tried swapping cables.

Try removing antenna from airframe, connecting it directly to radio and see if there is noise.

I can't explain it, but I know of one case where noise was coming via ground, and isolating the antenna from ground cured the problem. Perhaps a ground loop between coax shield and the airframe ground.



On 7/17/2015 7:51 AM, Ross Home wrote:



 	  Quote: 	
		  

I will try this. 

 

What is puzzling is that the antenna connection that leads to the rear antenna is at the firewall about 18 inches and level with my GX-60.  I can easily unhook the GX-60 cable from the front antenna (which is under the floor directly beneath the GX-60) and hook it to the rear antenna connection which is at the same height as the GX-60 and the noise goes away.  All of the wires that the GX-60 cable passes are the same in either case except, when it is connected to the front antenna, it crosses these wires at a 90 degree angle instead of running parallel to them when it goes the rear antenna connection. 	
	




  Routing of coax cables to antennas is NEVER

  a component of received noise . . . in the

  heavy iron we route coaxes where there is opportunity

  and room. The whole idea behind the industry standard

  practices for (1) limiting noise from antagonists,

  (2) improving resistance to noise by judicious

  design of potential victims and last (3) reducing

  risk of over-whelming propagation path (mounting

  an antenna under the cowl will probably pick up

  ignition noise). When a noise coming in through

  the receiver's antenna port is detected, placement

  of the coax isn't even a distant finisher in the

  quest for resolution.



  Assuming you have paid due diligence to standard practices

  for installing the two antennas then the fact that

  the forward-most antenna seems to be the key propagation

  port, then the noise source is most likely forward ON

  the aircraft. If it were off the aircraft, both

  antennas would hear it.



  This problem has a lot in common with Col_Mustard-

  did-it-in-the-library-with-a-rope . . . you gotta

  gather all the clues available to you BEFORE picking

  up hammers-n-saws . . . or screwdrivers.



  Antennas don't go BAD in a manner that makes one

  a source of noise while others are not. They either

  work good . . . or they don't . . . but they're never

  'noisy'. Start with a 'cold' panel and bring up

  equipment one item at a time . . . then confirm

  your preliminary findings with a sniffer receiver.



  Only THEN will hammers, saws and screwdrivers

  contribute to resolution of the problem.



  Bob . . .  	  Quote: 	
		    [b]http://www.matronics.com/Navigator?AeroElectric-List 	
0 	  Quote: 	
		   	
1 	  Quote: 	
		   	
2 	  Quote: 	
		   	
3 	  Quote: 	
		   	
4 	  Quote: 	
		   	
5 	  Quote: 	
		   	
6 	  Quote: 	
		   	
7

  [quote][b]

rossmickey(at)comcast.net
Guest

Posted: Sun Jul 19, 2015 11:17 am Post subject: Radio Buzz

I have identified that the buzz/static is coming from the new AFS 5600 EFIS I just installed. I have lessened the static sound some by re routing some wires. I also now can see that the rear antenna is being slightly affected also. All of the grounds look good going to a common ground block attached to the battery.  

Now what do I do?



Ross Mickey

On Jul 17, 2015, at 12:43 PM, Ross Home <rossmickey(at)comcast.net (rossmickey(at)comcast.net)> wrote:

[quote]  <![endif]-->   <![endif]-->

Thanks so much, Bob.  I will do as you suggest when I get back out to the hangar.  

 

Just for my education.  Since the location of the coax is not an issue, am I to understand that the interference I am experiencing is being picked up by the forward antenna itself?

 

In surfing the web about comm antenna, I read about the importance of having good electrical bonding of the antenna to the aircraft ground.

 

The electrical bonding of the antennas to the aircraft skin is best accomplished by direct metal-to metal contact of the antenna base to the aircraft skin. To accomplish this, the aircraft paint in the mounting area will need to be removed and the surface alodined to protect aluminum against corrosion. An alternate method for providing electrical bonding is through the mounting screws, which attach to a backing plate inside the aircraft skin. Remove any interior paint in the area where the backing plate is placed to assure a good ground. Coat this area with alodine to minimize corrosion. To test the electrical bonding of the blade to the aircraft, a reading of .003 ohms between the antenna base plate and ground should be achieved.

 

I am using the second method and will have to check if my installation meets the .003 ohm test.  If the front antenna does not meet this, would this cause a buzz or just degrade the performance of the antenna?

 

Ross

 

From: owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com) [mailto:owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com)] On Behalf Of Robert L. Nuckolls, III

Sent: Friday, July 17, 2015 11:45 AM

To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)

Subject: Re: Radio Buzz

 

At 11:05 AM 7/17/2015, you wrote:



 	  Quote: 	
		  

Since you have ruled out external sources, it sort of points to the front antenna cable. I thought you said you had tried swapping cables.

Try removing antenna from airframe, connecting it directly to radio and see if there is noise.

I can't explain it, but I know of one case where noise was coming via ground, and isolating the antenna from ground cured the problem. Perhaps a ground loop between coax shield and the airframe ground.



On 7/17/2015 7:51 AM, Ross Home wrote:



 	  Quote: 	
		  

I will try this. 

 

What is puzzling is that the antenna connection that leads to the rear antenna is at the firewall about 18 inches and level with my GX-60.  I can easily unhook the GX-60 cable from the front antenna (which is under the floor directly beneath the GX-60) and hook it to the rear antenna connection which is at the same height as the GX-60 and the noise goes away.  All of the wires that the GX-60 cable passes are the same in either case except, when it is connected to the front antenna, it crosses these wires at a 90 degree angle instead of running parallel to them when it goes the rear antenna connection. 	
	




  Routing of coax cables to antennas is NEVER

  a component of received noise . . . in the

  heavy iron we route coaxes where there is opportunity

  and room. The whole idea behind the industry standard

  practices for (1) limiting noise from antagonists,

  (2) improving resistance to noise by judicious

  design of potential victims and last (3) reducing

  risk of over-whelming propagation path (mounting

  an antenna under the cowl will probably pick up

  ignition noise). When a noise coming in through

  the receiver's antenna port is detected, placement

  of the coax isn't even a distant finisher in the

  quest for resolution.



  Assuming you have paid due diligence to standard practices

  for installing the two antennas then the fact that

  the forward-most antenna seems to be the key propagation

  port, then the noise source is most likely forward ON

  the aircraft. If it were off the aircraft, both

  antennas would hear it.



  This problem has a lot in common with Col_Mustard-

  did-it-in-the-library-with-a-rope . . . you gotta

  gather all the clues available to you BEFORE picking

  up hammers-n-saws . . . or screwdrivers.



  Antennas don't go BAD in a manner that makes one

  a source of noise while others are not. They either

  work good . . . or they don't . . . but they're never

  'noisy'. Start with a 'cold' panel and bring up

  equipment one item at a time . . . then confirm

  your preliminary findings with a sniffer receiver.



  Only THEN will hammers, saws and screwdrivers

  contribute to resolution of the problem.



  Bob . . .  	  Quote: 	
		    [b]http://www.matronics.com/Navigator?AeroElectric-List[/b][b][/b][b][/b] 	
0 	  Quote: 	
		   	
1 	  Quote: 	
		   	
2 	  Quote: 	
		   	
3 	  Quote: 	
		   	
4 	  Quote: 	
		   	
5 	  Quote: 	
		   	
6 	  Quote: 	
		   	
7

[b]   	  Quote: 	
		  [b] 	
8[/b][/b]

[b]

deej(at)deej.net
Guest

Posted: Sun Jul 19, 2015 11:26 am Post subject: Radio Buzz

On 7/19/2015 3:15 PM, Ross Mickey (home) wrote:

 	  Quote: 	
		   I have identified that the buzz/static is coming from the new AFS 5600

 EFIS I just installed.  

 

 Now what do I do?


	




First thing I'd do is contact AFS and see if they have any thoughts.

Others might have reported similar issues and they may have some ready

ideas to try.



-Dj



-- 

Dj Merrill - N1JOV - EAA Chapter 87

Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/

Glastar Flyer N866RH - http://deej.net/glastar/

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Sun Jul 19, 2015 1:11 pm Post subject: Radio Buzz

Turn the EFIS off with circuit breaker. See if the noise goes away. Then 

call AFS/Dynon for advice if that proves to be the source of the noise.



On 7/19/2015 12:15 PM, Ross Mickey (home) wrote:

 	  Quote: 	
		   I have identified that the buzz/static is coming from the new AFS 5600 

 EFIS I just installed. I have lessened the static sound some by re 

 routing some wires. I also now can see that the rear antenna is being 

 slightly affected also. All of the grounds look good going to a common 

 ground block attached to the battery.



 Now what do I do?



 Ross Mickey



 On Jul 17, 2015, at 12:43 PM, Ross Home <rossmickey(at)comcast.net 

 <mailto:rossmickey(at)comcast.net>> wrote:



> Thanks so much, Bob. I will do as you suggest when I get back out to 

> the hangar.

>

> Just for my education.  Since the location of the coax is not an 

> issue, am I to understand that the interference I am experiencing is 

> being picked up by the forward antenna itself?

>

> In surfing the web about comm antenna, I read about the importance of 

> having good electrical bonding of the antenna to the aircraft ground.

>

> The electrical bonding of the antennas to the aircraft skin is best 

> accomplished by direct metal-to metal contact of the antenna base to 

> the aircraft skin. To accomplish this, the aircraft paint in the 

> mounting area will need to be removed and the surface alodined to 

> protect aluminum against corrosion. An alternate method for providing 

> electrical bonding is through the mounting screws, which attach to a 

> backing plate inside the aircraft skin. Remove any interior paint in 

> the area where the backing plate is placed to assure a good ground. 

> Coat this area with alodine to minimize corrosion. To test the 

> electrical bonding of the blade to the aircraft, a reading of .003 

> ohms between the antenna base plate and ground should be achieved.

>

> I am using the second method and will have to check if my 

> installation meets the .003 ohm test.  If the front antenna does not 

> meet this, would this cause a buzz or just degrade the performance of 

> the antenna?

>

> Ross

>

> *From:*owner-aeroelectric-list-server(at)matronics.com 

> <mailto:owner-aeroelectric-list-server(at)matronics.com> 

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

> *Robert L. Nuckolls, III

> *Sent:* Friday, July 17, 2015 11:45 AM

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

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

> *Subject:* Re: Radio Buzz

>

> At 11:05 AM 7/17/2015, you wrote:

>

>     Since you have ruled out external sources, it sort of points to

>     the front antenna cable. I thought you said you had tried

>     swapping cables.

>     Try removing antenna from airframe, connecting it directly to

>     radio and see if there is noise.

>     I can't explain it, but I know of one case where noise was coming

>     via ground, and isolating the antenna from ground cured the

>     problem. Perhaps a ground loop between coax shield and the

>     airframe ground.

>

>     On 7/17/2015 7:51 AM, Ross Home wrote:

>

>         I will try this.

>

>         What is puzzling is that the antenna connection that leads to

>         the rear antenna is at the firewall about 18 inches and level

>         with my GX-60.  I can easily unhook the GX-60 cable from the

>         front antenna (which is under the floor directly beneath the

>         GX-60) and hook it to the rear antenna connection which is at

>         the same height as the GX-60 and the noise goes away.  All of

>         the wires that the GX-60 cable passes are the same in either

>         case except, when it is connected to the front antenna, it

>         crosses these wires at a 90 degree angle instead of running

>         parallel to them when it goes the rear antenna connection.

>   Routing of coax cables to antennas is NEVER

>   a component of received noise . . . in the

>   heavy iron we route coaxes where there is opportunity

>   and room. The whole idea behind the industry standard

>   practices for (1) limiting noise from antagonists,

>   (2) improving resistance to noise by judicious

>   design of potential victims and last (3) reducing

>   risk of over-whelming propagation path (mounting

>   an antenna under the cowl will probably pick up

>   ignition noise). When a noise coming in through

>   the receiver's antenna port is detected, placement

>   of the coax isn't even a distant finisher in the

>   quest for resolution.

>

>   Assuming you have paid due diligence to standard practices

>   for installing the two antennas then the fact that

>   the forward-most antenna seems to be the key propagation

>   port, then the noise source is most likely forward ON

>   the aircraft. If it were off the aircraft, both

>   antennas would hear it.

>

>   This problem has a lot in common with Col_Mustard-

>   did-it-in-the-library-with-a-rope . . . you gotta

>   gather all the clues available to you BEFORE picking

>   up hammers-n-saws . . . or screwdrivers.

>

>   Antennas don't go BAD in a manner that makes one

>   a source of noise while others are not. They either

>   work good . . . or they don't . . . but they're never

>   'noisy'. Start with a 'cold' panel and bring up

>   equipment one item at a time . . . then confirm

>   your preliminary findings with a sniffer receiver.

>

>   Only THEN will hammers, saws and screwdrivers

>   contribute to resolution of the problem.

>   Bob . . .

>

> **

> **

> **

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> **

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

> ****

> ****

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_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

user9253

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

Posted: Sun Jul 19, 2015 2:06 pm Post subject: Re: Radio Buzz

Is the AFS 5600 EFIS wired according to the installation manual?  Usually shielded cables are grounded at the source end only, but not always.  Can you identify one or more wires from the AFS 5600 EFIS that are causing the noise?

  Is the squelch on the com radio adjusted too sensitive?

Joe

_________________
Joe Gores

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