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  #101  
Old 01-27-2014, 05:07 PM
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rocketbob rocketbob is offline
 
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This is the ferrite I used: http://www.mpja.com/025in-ID-Ferrite...nfo/18466%20FL

Note that this ferrite core is significantly more substantial than the radio shack ferrite.

I tried several different capacitors of varying capacitance and types and did not find much of a change.

On my santa wish list is a spectrum analyzer to determine exactly what frequencies things like these LED lights bark at.
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  #102  
Old 01-27-2014, 05:37 PM
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bullojm1 bullojm1 is offline
 
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Quote:
Originally Posted by rocketbob View Post
On my santa wish list is a spectrum analyzer to determine exactly what frequencies things like these LED lights bark at.
Bob,

Have you ever looked at using a Software Defined Radio (SDR) spectrum analyzer? I was quite impressed with using the free Windows program SDRSharp(http://sdrsharp.com/) with an inexpensive USB SDR dongle (RTL2832U & R820T). You can pick up the USB SDR Dongle for about $15 shipped on Ebay. It works quite well - I have been able to detect 978Mhz and 1090Mhz ADS-B signals, AM, FM, Digital television and APRS signals. I am sure it would be good enough to find the frequency of the noise coming off these LED's.
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  #103  
Old 01-27-2014, 05:45 PM
Bavafa Bavafa is offline
 
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Quote:
Originally Posted by Toobuilder View Post
One of my EE guys suggested a .1uF capacitor between power and ground, close to the light as possible.
How about using a shielded wire for the landing light? Do you guys think that would supperss all RFI?

I used the capacitor for my HID with no effect, not to say that it may not be useful in this situation.

I really like these flashlight type for LL if I find a solution for the RFI.
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  #104  
Old 01-27-2014, 06:34 PM
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catmandu catmandu is offline
 
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Quote:
Originally Posted by rocketbob View Post
This is the ferrite I used: http://www.mpja.com/025in-ID-Ferrite...nfo/18466%20FL

Note that this ferrite core is significantly more substantial than the radio shack ferrite.
That IS quite the ferrite, and good price. Think I'll order a few. In the meantime, I'll try some shielded wire tomorrow.
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  #105  
Old 01-27-2014, 07:13 PM
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rocketbob rocketbob is offline
 
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Quote:
Originally Posted by bullojm1 View Post
Bob,

Have you ever looked at using a Software Defined Radio (SDR) spectrum analyzer? I was quite impressed with using the free Windows program SDRSharp(http://sdrsharp.com/) with an inexpensive USB SDR dongle (RTL2832U & R820T). You can pick up the USB SDR Dongle for about $15 shipped on Ebay. It works quite well - I have been able to detect 978Mhz and 1090Mhz ADS-B signals, AM, FM, Digital television and APRS signals. I am sure it would be good enough to find the frequency of the noise coming off these LED's.
Yep I have been playing around with SDR#. Very cool indeed. I have thought it could be used as a spectrum analyzer, albeit one without any filtering.
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Bob Japundza CFI A&PIA
N9187P PA-24-260B Comanche, flying
N678X F1 Rocket, under const.
N244BJ RV-6 "victim of SNF tornado" 1200+ hrs, rebuilding
N8155F C150 flying
N7925P PA-24-250 Comanche, restoring
Not a thing I own is stock.
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  #106  
Old 01-28-2014, 10:04 AM
tikicarver tikicarver is offline
 
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Location: Tehachapi,CA
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I think I can get access to a spectrum analyzer at work. If so, I'll hook my light to it and post the results.
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  #107  
Old 01-28-2014, 10:45 AM
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Toobuilder Toobuilder is offline
 
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How about bringing it over to my house (I'm off this Friday) and we can compare the two versions of this light?
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  #108  
Old 01-28-2014, 10:57 AM
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fl-mike fl-mike is offline
 
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I don't have need for one of these right now, but I do have access to a anechoic EMI room and test gear. I can do a full DO-160 radiated and conducted emissions screen on one if somebody wants to drop ship one to me. I'm kind of the resident EMI "fixer", at least on the stuff I don't design...
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  #109  
Old 01-28-2014, 11:38 AM
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wirejock wirejock is offline
 
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Default RFI

I haven't done board level radio in a long time but I did stay in a Holiday Inn last night!
Sorry, couldn't resist.
Is it possible the RFI is coming from the light itself. Wrap that thing with aluminum foil and turn it on for a few seconds. Just long enough to see. If I read correctly, it's pretty close to the antenna.
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  #110  
Old 01-31-2014, 09:22 PM
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catmandu catmandu is offline
 
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Tried using shielded wire today, no change. Bummer. Might have to abandon the trustfire.
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