[Elecraft] Noise from LEDs

[Robert Nobis]

Hi John,

Possibly the undercounted LEDs or their power supply are defective and should be replaced.  I have about 30 LED light bulbs of various types in my house and I have not experienced any issues with an increase in the noise floor.  

73,

Bob Nobis - N7RJN
n7rjn at nobis.net


> On Feb 1, 2016, at 20:48, johnpierce <ja-pierce at verizon.net> 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
> 
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