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Radio noise with HID lights

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Gilles.Thesee(at)ac-greno
Guest

Posted: Sat Apr 15, 2006 2:27 am Post subject: Radio noise with HID lights

Hi Bob and all,



A buddy is submitting the following :



He installed two auto-conversion HID lights on his MCR 01 gear legs. The 

ballast boxes are in the fuselage, with 18 inch high tension leads. The 

VHF antenna is under the fuselage, about 5-7 feet behind the boxes.

He is experiencing radio noise at frequencies below 120 MHz. Noise is 

not audible during lights warmup, only when warm.

He tried feeding the HID boxes with an independant battery, to no avail. 

Noise is heard also with a handheld radio.



Any idea how to work around this problem ?



Thanks in advance,



Regards,

Gilles Thesee

Grenoble, France

http://contrails.free.fr

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nuckollsr(at)cox.net
Guest

Posted: Sat Apr 15, 2006 5:46 am Post subject: Radio noise with HID lights

At 12:14 PM 4/15/2006 +0200, you wrote:



 	  Quote: 	
		  

<Gilles.Thesee(at)ac-grenoble.fr>



Hi Bob and all,



A buddy is submitting the following :



He installed two auto-conversion HID lights on his MCR 01 gear legs. The

ballast boxes are in the fuselage, with 18 inch high tension leads. The

VHF antenna is under the fuselage, about 5-7 feet behind the boxes.

He is experiencing radio noise at frequencies below 120 MHz. Noise is

not audible during lights warmup, only when warm.

He tried feeding the HID boxes with an independant battery, to no avail.

Noise is heard also with a handheld radio.


	




 	  Quote: 	
		  Any idea how to work around this problem ?


	


    The usual approach is to take the device to the RF

    lab to research the propagation mode for noise

    and then deduce mitigation techniques. It's exceedingly

    difficult to offer specific recommendations

    without putting one's hands on the hardware

    and probing it's characteristics with the

    appropriate tools.



    The broad-brush advice would include things

    like shielded enclosures and filtered penetrations

    for wires. However, one needs to be mindful of

    possible deleterious effects of filters

    on proper operation of the system. He could

    try ferrite beads on the leads, and enclosing

    all the electronics in a metal box.



        Bob . . .

      < What is so wonderful about scientific truth...is that >

      < the authority which determines whether there can be   >

      < debate or not does not reside in some fraternity of   >

      < scientists; nor is it divine. The authority rests     >

      < with experiment.                                      >

      <                            --Lawrence M. Krauss       >

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Gilles.Thesee(at)ac-greno
Guest

Posted: Sat Apr 15, 2006 6:28 am Post subject: Radio noise with HID lights

 	  Quote: 	
		  > Any idea how to work around this problem ?

>     



     The usual approach is to take the device to the RF

     lab to research the propagation mode for noise

     and then deduce mitigation techniques. It's exceedingly

     difficult to offer specific recommendations

     without putting one's hands on the hardware

     and probing it's characteristics with the

     appropriate tools.



     The broad-brush advice would include things

     like shielded enclosures and filtered penetrations

     for wires. However, one needs to be mindful of

     possible deleterious effects of filters

     on proper operation of the system. He could

     try ferrite beads on the leads, and enclosing

     all the electronics in a metal box.

   

Bob,
	




Thank you for your quick answer. I'm passing it on to him.



Regards,

Gilles Thesee

Grenoble, France

http://contrails.free.fr

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aadamson(at)highrf.com
Guest

Posted: Sat Apr 15, 2006 7:07 am Post subject: Radio noise with HID lights

One note about HID's, they are a High voltage type light, and the "starter"

and "ballast" use a pulse mechanism to start them and then keep them lit.

It usually provides 50-80V to the lamp its self, but at very low current.



The eletronics use some form of "step up" converter, They usually call these

things "boost pumps" because they cycle at a very fast rate (creating EMI,

RFI) to create the additional voltage required.  If the Ballast is not

"shielded" then you are asking for this type of interference.  Is the

Ballast plastic or metal? 



Alan



--

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Gilles.Thesee(at)ac-greno
Guest

Posted: Sat Apr 15, 2006 9:09 am Post subject: Radio noise with HID lights

Alan K. Adamson a crit :

 	  Quote: 	
		   



 One note about HID's, they are a High voltage type light, and the "starter"

 and "ballast" use a pulse mechanism to start them and then keep them lit.

 It usually provides 50-80V to the lamp its self, but at very low current.



 The eletronics use some form of "step up" converter, They usually call these

 things "boost pumps" because they cycle at a very fast rate (creating EMI,

 RFI) to create the additional voltage required.  If the Ballast is not

 "shielded" then you are asking for this type of interference.  Is the

 Ballast plastic or metal? 



   

Alan,
	




Thank you for your input.

I don't know what my buddy's ballast case is made of. Il ask him.



Regards,

Gilles Thesee

Grenoble, France

http://contrails.free.fr

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

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