[RFI] LED Bulbs

David C. Hallam dhallam at knology.net
Mon Feb 10 07:35:30 EST 2014

The following is part of a message I received from a ham friend of mine 
who lives in Northern New Jersey.


> I've been tearing my hair out for 2 months because of unbelievable RFI on 2
> meters, rendering terrestrial and EME impossible. The following text pretty
> much sums up what I finally found today. This may be a big problem because
> the FCC considers that once identified, the liability for correction is on
> the generator of the RFI and if not stopped immediately then they can be
> fined. Who would have thought the LED's could radiate so far? If you want to
> see some pictures from the spectrum analyzer I'll send them down. You
> wouldn't believe it!
> "At last the source of the RFI has been positively identified!
> To recap, the wideband RFI centered on 145 MHz which began in mid-December
> was isolated to a specific house at 22 Cedars Road in Caldwell, NJ about 700
> feet from my home. The RF level was about 20db over S-9 or nearly 1
> millivolt, yes, "millivolt' at my receiver. It wiped out the entire 2 meter
> band as well as the lower portion of the public safety and aircraft
> spectrum.
> While the RFI sounded like AC line buzz, looking at it on a spectrum
> analyzer showed a 20 MHz wide signal that swept and pulsated. PSEG was
> instrumental in first identifying that the RFI was wideband and close to the
> residence in question as I had determined from walking the area. I then used
> a 4 element 2 meter yagi to positively identify the direction of the source.
> I considered that the problem might be channel 18 leakage from Comcast cable
> but that did not prove to be the case.
> I was able to talk to the home owner who was very cooperative in working
> with me to find the source. I first thought that it was associated with TV
> usage but several tests did not yield the precise problem though the
> Comacast cable box and Samsung large screen TV were able to be heard inside
> the house on my Yaesu HT in AM mode but nowhere near the level I was seeing
> at times at my home. It seemed that when the homeowner was not home the RFI
> would disappear and in that case TV's were off.
> Today, another test was made where the homeowner turned off all TV's and the
> RFI was still present. She then started tripping breakers and the RFI
> completely disappeared! It was now positive that the RFI was from something
> I the home. Further testing revealed the source as 9 LED lamps in the
> kitchen that had been installed in mid-December, at the time I first noticed
> the beginning of the problem.
> The lamps were obtained at Home Depot and are the Eco-Smart brand, MR-16
> halogen replacements and are rated at 50w = 8 watts consumption. Obviously
> this is going to become a really big problem, not only for PSEG as people
> bite the bullet and purchase these things but it will also become a FCC
> issue as well as they clearly exceed any radiated emission spec's for
> consumer devices.
> For now, since we know the source of the problem, I am working out with the
> homeowner a plan to perhaps go back to the halogen lamps. This problem needs
> to be escalated to Home Depot, the FCC, and anybody else that should be
> notified before the entire 2 meter spectrum is lost to licensed users in
> this country and others."

"I predict future happiness for Americans if they can prevent the government from wasting the labors of the people under the pretense of taking care of them."
Thomas Jefferson

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