[AMRadio] Traffic Light interference

sbjohnston at aol.com sbjohnston at aol.com
Sun Dec 2 22:49:23 EST 2007

<wb5oxq at grandecom.net> wrote:

>Just wait until the dept of transportation installs one of those new 
>traffic signals near you.  The switching power supplies they use are 
>noisy.  Those signal lights will break squelch on my mobile at least 
>yards away.  My friend N5IT who works for TEXDOT tells me he knows the
>devices are noisy but the manufacture does nothing about them.

The LED traffic lights that I've run into are very noisy in the FM 
broadcast band and will actually drown out an otherwise completely 
listenable signal when a car rolls up the light.  In my professional 
life I documented the interference thoroughly, including quite a list 
of listener complaints, and after a year of offering my help and trying 
to get the local city transportation dept to do something without 
success, I passed it along to the FCC.  I had to push pretty hard, but 
finally an FCC inspector engineer came out to check it (only because he 
was in town for something else).  He confirmed my finding but said, 
"Uh, well, it only bothers the weaker signals, so it is OK."  I pointed 
out that it was causing harmful interference to many listeners, and he 
just said they should find a stronger station to listen to.

What a joke.

Steve WD8DAS

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