[Milsurplus] LED Lighting and EMI

[J. Forster]

A friend asks:

My biggest question about LED lighting is how much radio interference it
generates at frequencies up to about 30 MHz (HF).  Other users of the
radio spectrum are more concerned by interference at higher frequencies,
through VHF and UHF.

AFAIK, an LED by itself does not generate radio interference; it is the
electronics between the LEDs and the AC power line that concerns me.

Fluorescent lights (both CFLs and long straight tubes) with electronic
ballasts are bad because an electronic ballast switches AC line power with
very short rise & fall times, so the ballast strongly excites the line
with radio-frequency power at whole-number multiples of the switching
frequency up to 30 MHz and beyond.

It is possible to reduce this radio “noise” or interference to a tolerable
level by means of shields, L-C filters, and ferrite chokes; but very few
manufacturers of fluorescent lighting products do.  If they do anything,
it is nowhere near enough.

I’m waiting for the prices of LED-lighting products to drop further before
I buy some for evaluation.  Meanwhile, can anyone direct us to published,
quantitative information about the radio noise generated by LED lighting
products?


Best,

-John

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