I live in the country with no traffic lights nearby, so this isn't a problem
with me, but I keep hearing about RFI generated by the new l.e.d. traffic
signals. Apparently, the noise is due to a switching power supply used to feed
the lights, and the power line leading to the unit acting as an antenna.
Someone I know has one of those LED stoplights about 100 yards from his house.
It wipes out the AM BC Band when you are in the car sitting at the light, and
he says he can hear it up and down the band and weaker signals on 75 and 160
at night are GONE. He figures there isn't anything he can do about it at all,
I wonder if anyone has checked to see if those led traffic lights have been
certified to meet Part 15 standards. Since they are becoming ubiquitous in
almost every city and town and there are traffic lights literally everywhere,
this could grow into a major rfi problem that rivals or surpasses BPL.
Perhaps the AM broadcast industry would get involved, since this stands to hurt
them severely. Over 90% of the prime time radio audience during morning and
evening hours is made up of commuters, and most listeners will simply switch
over to FM if they start getting interference at every traffic light. This
could become the death knell for AM broadcast radio, with its odds for survival
already marginal at best. Those switching power supplies could easily be fixed
with a little filtering. I'm not even sure that shielding would be required.
This is a problem that needs to be addressed NOW before the overwhelming
majority of traffic signals nationwide are replaced with noisy l.e.d. ones and
the problem becomes impossible to remedy.
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