[Elecraft] Fluorescent RFI solved
David Christ
radioham at mchsi.com
Sat Nov 26 19:39:33 EST 2022
I have been buying Feit bulbs and fixtures from Costco for some time now and have never found any interference. I like their 4 foot shop lights. I have not tested the color changing bulbs.
David K0LUM
> On Nov 26, 2022, at 4:05 PM, Al Lorona <alorona at sbcglobal.net> wrote:
>
> I hope this helps anybody facing the same issue.
>
> The fluorescent lights in my basement make horrible RFI noise, especially on 40 m but really affecting all bands. They raise the noise floor by about 16 dB on 40. I discovered this during Field Day *last* year when I set up in the back yard.
>
> They use these electronic ballasts that put out perfect square waves -- that's the source of the noise. The entire bulb and wiring act as a radiator, and there's about 8 feet of wiring in each fixture. I did some research on the web and found a guy with the same lights who had disassembled every one of his fixtures to install filter capacitors, and I considered following his procedure but decided it was waaay too much work to undertake, so I've lived with the problem for a year-and-a-half.
>
> Anyway, at Menard's the other day I noticed these Feit LED replacements for the 4-foot fluorescent tubes. These have existed for years now, but these bulbs were different. They said "ballast bypass" on the box, and upon closer reading I learned that to use these as replacements you have to re-wire your fixtures by taking the ballast out of the circuit. (They're also called "direct wire" bulbs.) The hot and neutral go directly to the bulbs without anything else in between, just like incandescents used to be. Well, this intrigued me because I wondered if, with the ballast out of the loop, it would quiet things down.
>
> So I bought a few of them-- they're not too costly-- and re-wired one of my 4 fixtures and with the lights on I noticed that the noise floor had actually lowered perceptibly (and on the panadapter). I immediately went back to buy the 14 more bulbs I needed and now I can't even tell that the lights are on... there's no RF noise! So these LEDs are the answer to the evil electronic ballasts that I don't know how they got past the FCC. When purchasing LED bulbs one always risks incurring more noise from the LED circuitry itself, but I've always had pretty good experience with Feit and this was no exception. I can't speak for other brands.
>
> R,
>
> Al W6LX/4
>
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