[RFI] Fw: LED light bar RFI (UPDATE)

[Dan Kovatch]

----- Original Message ----- 
From: "Dan Kovatch" <w8car at buckeye-express.com>
To: <rfi at contesting.com>
Sent: Wednesday, February 03, 2010 7:34 AM
Subject: [RFI] LED light bar RFI


>I have several nice LED light bars as under cabinet lighting. Very 
>efficient
> power wise but they make more RFI across all the bands up through 6 meters
> than the old switching supply I had with halogens. They use a 'constant
> current' wall wart type supply and replacing them with a linear 
> transformer
> supply causes low light output probably because of the lack of constant
> current. Another LED bar across the kitchen (different make) has no issues
> with noise.
>
> I have tried ferrite beads to no effect. Has anyone had luck taming these
> critters?
>
> Dan W8CAR
>
> _______________________________________________
>

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 hassel.

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