[RFI] RFI from LED power supplies

Dan Kovatch w8car at buckeye-express.com
Thu Mar 17 07:57:57 PDT 2011


With the comments on LEDs I was reminded of the post I made a while ago. I 
copied it and reposted it below. Most important, I tried a linear power 
supply to replace the wall warts with no success. The lights only glowed 
dimly, if at all.

The repost is below:::

After trying all the ideas presented here and from other sources I still had
not conquered the RFI from the 'wall wart' noise generators. After  winding
wires both input (AC side) and output (DC to LEDS)  around appropriate cores
I went searching on Jameco for constant current supplies. I found one that
had 1.1 amp output-enough to replace all three of the wall warts. I ordered
it figuring that even if it made noise the extra space I gained back by not
having the warts in the way (the new supply mounts under the cabinet like
the lights) I would still be ahead.

The final result is NO discernable noise on any band-especially 160 where
they wiped out my rcvr antennas completely. I post the model numbers and
manufacturers below in hopes it may save someone else some future hassle.

The wall warts are from MDL corp p/n 319-00047 led power supply direct plug
in 350ma constant current, 35VDC (the actual voltage measured around 28DC)

The replacement is a Meanwell LPC-35-1050 (9-30VDC @1.05 amp)

My wife is happy, the roll of tape in the kitchen is happy and most of all
stubborness and technology have once again been put into harmony.

Dan W8CAR 



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