Bill,
I think I remember this subject being discussed in another venue,
possibly on YahooGroups. In that case, if I recall correctly, the
noise was evidently coming from a switching power supply providing
low-voltage for LED lamps.
It does not need mentioning that harmful interference requires
correction. I would not be surprised, however, to learn the power
supplies used in the lights were NOT in compliance, the manufacturer
having evaded that by reliance on the utility exemption Part 15
provides. However, that exemption does not apply to equipment located
outside of a utility's facility and harmful interference in any event
voids it.
I may take a look at a few lights around here (Sonoma County,CA) with a
receiver or a spectrum analyzer to see what's coming from them. I've GOT
time;
no one is hiring EMI engineers just now (rueful grin).
Cortland
William G. McDowell <k4cia@mindspring.com> wrote"
>
> Has anyone experienced RFI from these new LED traffic lights? I live
about
> 800' from an intersection that has several of them. A broad band RF
> emission is radiated when the red and green lights are illuminated. The
> noise stops when yellow (caution) is lit as the lights change. Sounds
just
> like line noise on the receiver but its coming from the lights. I've
> confirmed this by using a portable SW near the intersection.
> Any advice appreciated. Have called a state traffic light engineer but
did
> not get a return call yet.
>
> Yet another obstacle to overcome in this quest for semi-quiet bands.
>
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