When I bought some LED fixtures for the kitchen a few years ago, I
connected a power cord to them at home and tested them for RFI before
installing them. All were OK. One of my neighbors unwittingly helped me
identify a quiet power supply for LED light strings, by having a very
noisy one, The vendor replaced it with one from a different
manufacturer, which was quiet. I bought some of those for my own home.
73,
Scott K9MA
On 2/1/2023 4:07 PM, Pete Smith N4ZR wrote:
Very interesting and timely (at least for me). I am at the beginning
of an extensive basement redo, which will involve on the order of a
dozen round 6-watt equivalent LED lights in the ceiling. I was
concerned about the same sort of problem, so I bought one example and
plugged it into an outlet strip on my operating desk. I could find no
RFI anywhere in HF (or rather nothing that turned on and off with the
light fixture).
For anyone who wants to know, the light I tested is a Commercial
Electric 6" recessed light kit. It is made in Thailand and sold by
Home Depot. The item number is 1005 591 792. The light itself feels
like there is a transformer behind the LED panel - simply based on
weight. I wrote to Commercial Electric to inquire, and the only
response I got was, essentially, "Huh?"
Do those of you who understand such things, more than I do, think that
I'm probably safe in going ahead with these units, based on my test?
73, Pete N4ZR
On 2/1/2023 4:22 PM, Gary NA6O via RFI wrote:
On 2/1/2023 4:52 AM, K9MA wrote:
Besides the preponderance of 120 Hz harmonics in the AM audio, the
very broadband nature of line noise is usually the main indicator.
120 Hz is also a strong component of electronic noise generated by
power supplies and power control equipment. The audio spectrum is not
a great clue -- the RF/IF waterfall shows where the bodies are buried.
73, Jim K9YC
_______________________________________________
That's true, but I have never seen broadband noise with 120 Hz
harmonics
in the AM audio which was NOT power line noise. And, alas, I've seen a
lot of line noise.
73,
Scott K9MA
I have an LED fixture for you that produces 120 Hz buzz over decades
of bandwidth, nearly indistinguishable from an arcing power line: The
Elite RL675. Twenty-one of these, installed next door, resulted in a
1.5 year shootout including ARRL and the FCC and even after
mitigation left my home station permanently QRT. Yes, it can be that
bad... Full story is on my RFI page. Here are detailed measurements
on said fixture:
https://na6o.com/main/RFI_files/Elite%20RL675%20RFI%20Test%20Report.pdf
<https://na6o.com/main/RFI_files/Elite%20RL675%20RFI%20Test%20Report.pdf>
73,
Gary NA6O
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Scott K9MA
k9ma@sdellington.us
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