[Elecraft] Noise from LEDs

[Bob McGraw K4TAX]

As Dave, NK7Z stated in part 2:  "If I have a RF generating wall wart, 
it is best to remove it and replace it with one that does not generate 
RFI, not just put ferrite material on it."

 From this and your description, I would speculate the power supply is 
the guilty party that is creating the RFI and it should be replaced.  
Case and point, I went through three different chargers for my HP laptop 
before I found one that didn't create RFI issues. And note too, they 
were all "certified" according to the labeling on their cases.

73
Bob, K4TAX



On 2/1/2016 9:48 PM, johnpierce wrote:
> My kitchen, under cabinet lights, are LEDs.  With those lights turned on my
> noise floor changes from -128db to -102db.  If the circuit is changed to a
> different phase the noise improves by 6db.  All of this at 7mhz and other
> higher bands.  Needless to say the AM broadcast band is highly affected by
> the LEDs.
>
>   
>
> Placing a type 31 core with three turn of the AC line feeding the LED power
> supply and a clamp on 31 core on the LED side of the power supply provides
> no improvement!  I do not have an oscilloscope to look at the waveforms.
> But given what I have done, why is there no improvement?  I was following
> recommendations provided by NK7Z.
>
>   
>
> AD2F,  John
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to rmcgraw at blomand.net
>