Matronics Email Lists :: View topic - Strobe discharge pop-pop-pop

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

Strobe discharge pop-pop-pop

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

recapen(at)earthlink.net
Guest

Posted: Wed Jan 09, 2008 10:59 am Post subject: Strobe discharge pop-pop-pop

I'm doing some system testing and I can hear a very slight pop each time my strobes discharge through my headset.  It doesn't break the squelch or prevent me from hearing the radios - or stereo for that matter.  No whining on the charge cycles and I gotta listen carefully to catch the pop - but it's there.



Is this strictly due to the high-voltage discharge in a 12V system?  Is there something I can due to get rid of this?  Or should I take gladness that it's faint, doesn't interfere, it's as good as it gets, have a coke and a smile and.......?



Ralph

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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

klehman(at)albedo.net
Guest

Posted: Wed Jan 09, 2008 8:47 pm Post subject: Strobe discharge pop-pop-pop

Ralph

Have you tried it outside? My radio picks it up when in a metal hangar 

but not when outside. My intercom picks up a little as well via power 

supply or ground but hardly noticeable with the engine idling. So it 

might not be worth pursuing. The chapter on noise and grounding may be 

helpful. And if it is still noticeable a cheap automotive radio power 

filter on the strobe power supplies also helped in my case.

Ken



Ralph E. Capen wrote:

 	  Quote: 	
		   

 

 I'm doing some system testing and I can hear a very slight pop each time my strobes discharge through my headset.  It doesn't break the squelch or prevent me from hearing the radios - or stereo for that matter.  No whining on the charge cycles and I gotta listen carefully to catch the pop - but it's there.

 

 Is this strictly due to the high-voltage discharge in a 12V system?  Is there something I can due to get rid of this?  Or should I take gladness that it's faint, doesn't interfere, it's as good as it gets, have a coke and a smile and.......?

 

 Ralph

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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

recapen(at)earthlink.net
Guest

Posted: Thu Jan 10, 2008 5:17 am Post subject: Strobe discharge pop-pop-pop

I'll be trying it outside soon and with the engine later - I'm almost thinking the engine will drown it out...



--

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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

nuckolls.bob(at)cox.net
Guest

Posted: Thu Jan 10, 2008 5:41 pm Post subject: Strobe discharge pop-pop-pop

At 01:36 PM 1/9/2008 -0500, you wrote:



 	  Quote: 	
		  

<recapen(at)earthlink.net>



I'm doing some system testing and I can hear a very slight pop each time 

my strobes discharge through my headset.  It doesn't break the squelch or 

prevent me from hearing the radios - or stereo for that matter.  No 

whining on the charge cycles and I gotta listen carefully to catch the pop 

- but it's there.



Is this strictly due to the high-voltage discharge in a 12V system?  Is 

there something I can due to get rid of this?  Or should I take gladness 

that it's faint, doesn't interfere, it's as good as it gets, have a coke 

and a smile and.......?


	


   When you think about the physics of what's going

   on inside a xenon flash-tube, it has a great deal

   in common with a lightning strike. As we all know,

   a lighting strike can be "felt" both in terms of

   magnetic and electrostatic effects, both of which

   have the ability to radiate some distance and/or

   couple to conductors.



   What you're hearing is the broad spectrum, radiated

   noise coming directly from the confines of the ionized

   gasses in the tube when it fires.



   When we put the first strobes on Cessna single-engine

   airplanes in the 60's, there was a lot of fuss about

   this mini-strike being heard in the ADF receivers.

   We tried some glass with conductive coatings (reduced

   light output) and fine-mesh screen wire (really hard to

   work with).



   Somebody finally noted that, "Bee, when you're tuned to

   a station that was strong enough to be useable for either

   listening or navigating, the "pop" was imperceptible

   and effects on navigation nil."



   Chances are that in flight, you're going to discover

   the same thing. Now, if it does turn out to be a problem,

   you'll need to repeat the same experiments we tried 40

   years ago and perhaps some new ones. I'm aware of no

   current tricks of the trade that would a apply.



   Bob . . .

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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

jpx(at)Qenesis.com
Guest

Posted: Sat Jan 12, 2008 8:44 am Post subject: Strobe discharge pop-pop-pop

Ralph,



I had this same problem with the strobes in my Cessna 172.

I solved it by inserting a 1N4002 diode in the power feed to my  

intercom and putting a 2200uF/35V capacitor between power and ground  

on the intercom side.

Unfortunately this was after rewiring all the intercom wires which had  

been shoddily installed and incorrectly grounded at both ends.  Parts  

were what I had at hand.  It is an easy thing to for you to try.



I also found the problem was much more noticable when testing on the  

ground when the alternator was not running to boost the voltage than  

when flying.



Jeff Page

Dream Aircraft Tundra #10



 	  Quote: 	
		   From: "Ralph E. Capen" <recapen(at)earthlink.net>

 Subject: Strobe discharge pop-pop-pop



 I'm doing some system testing and I can hear a very slight pop each time my

 strobes discharge through my headset.  It doesn't break the squelch or

 prevent me from hearing the radios - or stereo for that matter.  No whining

 on the charge cycles and I gotta listen carefully to catch the pop - but it's

 there.



 Is this strictly due to the high-voltage discharge in a 12V system?

 Is there something I can due to get rid of this?  Or should I take gladness

 that it's faint, doesn't interfere, it's as good as it gets, have a coke and

 a smile and.......?



 Ralph

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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

nuckolls.bob(at)cox.net
Guest

Posted: Sat Jan 12, 2008 9:17 am Post subject: Strobe discharge pop-pop-pop

At 11:25 AM 1/12/2008 -0500, you wrote:



 	  Quote: 	
		  



Ralph,



I had this same problem with the strobes in my Cessna 172.

I solved it by inserting a 1N4002 diode in the power feed to my

intercom and putting a 2200uF/35V capacitor between power and ground

on the intercom side.

Unfortunately this was after rewiring all the intercom wires which had

been shoddily installed and incorrectly grounded at both ends.  Parts

were what I had at hand.  It is an easy thing to for you to try.



I also found the problem was much more noticable when testing on the

ground when the alternator was not running to boost the voltage than

when flying.


	


   Interesting! This demonstrates that the noise is conducted

   and the only way that the flash-tube circuit can couple to

   ship's wiring is magnetic or electrostatic. Twisting of

   the strobe head wires under a shield takes care of both of

   these coupling modes except where a ground loop (something

   connected to airframe at fixture end of wires).



   As an experiment, try operating your victim system(s) from

   their own quiet power source . . . say a couple of 6v lantern

   batteries in series. Get some el-cheesos from Wal-Mart.

   If the noise goes away while powered only by the batteries,

   then it's coming in through the +14v power wires. In this case,

   adding the diode and capacitor as cited above is worth exploring.



   Alternatively, it's worth exploring how the admittedly intense

   flash tube noises are getting out of their normally tight

   confines.



   Bob . . .

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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

jpx(at)Qenesis.com
Guest

Posted: Sun Jan 13, 2008 8:39 am Post subject: Strobe discharge pop-pop-pop

 	  Quote: 	
		   >Ralph,

 >

 >I had this same problem with the strobes in my Cessna 172.

 >I solved it by inserting a 1N4002 diode in the power feed to my

 >intercom and putting a 2200uF/35V capacitor between power and ground

 >on the intercom side.

 >Unfortunately this was after rewiring all the intercom wires which had

 >been shoddily installed and incorrectly grounded at both ends.  Parts

 >were what I had at hand.  It is an easy thing to for you to try.

 >

 >I also found the problem was much more noticable when testing on the

 >ground when the alternator was not running to boost the voltage than

 >when flying.



    Interesting! This demonstrates that the noise is conducted

    and the only way that the flash-tube circuit can couple to

    ship's wiring is magnetic or electrostatic. Twisting of

    the strobe head wires under a shield takes care of both of

    these coupling modes except where a ground loop (something

    connected to airframe at fixture end of wires).



    As an experiment, try operating your victim system(s) from

    their own quiet power source . . . say a couple of 6v lantern

    batteries in series. Get some el-cheesos from Wal-Mart.

    If the noise goes away while powered only by the batteries,

    then it's coming in through the +14v power wires. In this case,

    adding the diode and capacitor as cited above is worth exploring.



    Alternatively, it's worth exploring how the admittedly intense

    flash tube noises are getting out of their normally tight

    confines.



    Bob . . .


	


In my case, I think the noise wasn't from the discharge itself, but  

from the initial surge current as the strobe power pack started to  

re-charge its internal capacitors for the next flash.  I expect the  

inconsistent connection of power and ground to the strobes and  

intercom led to a voltage drop across the power feed wire to the  

intercom - apparently all the folks who worked on the airplane in its  

37 year history hadn't read your book 

The internal circuitry of the intercom was unable to compensate for  

the power fluctuation, which isn't a surprise to me considering the  

extremely poor design of the internal circuitry of the intercom -  

sometimes products are popular because of features and price, not  

quality 

In my case, it was just as easy to try sticking the diode and  

capacitor in the line as a test as it would have been to try using  

separate batteries as a power source. It worked so well that I left  

them there, rathering than trying to optimize the values.



Jeff Page

Dream Aircraft Tundra #10

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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

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