[RFI] Streetlight RFI Solution

Michael C Martin rfiservices at erols.com
Mon Jun 2 20:36:34 EDT 2003

Street lights are common cause of RI.
It is highly unlikely that the street light head was replaced. It is
probably a High Pressure Sodium (HPS). These are the most common type
that causes RFI. The cause can be the bulb, the transformer/ballast or
the photo cell. The photo cell is most likely the cause. The rest of the
circuit should be de-energized if the photo cell is working properly.
During the daytime, if a dark colored cup is placed over the top of the
fixture, covering the photocell, the light will come on and your RFI
should stop. The light will think it's night time. 
The problem is, when they test them on the street, they put their hand
or a glove over the photo cell. They wait for it to come on and if it
does they think it's ok. In your case it's an RFI source when in the off
If you can be there when they are going to do the repair, have a radio
with the noise active. Show them that the noise stops when a night time
condition is simulated.
The circuit does affect the signal strength because the wiring is the
antenna for the noise source. However, the majority of street light
sources I find use aluminum poles and they cause RI to the lower bands
many blocks away.
One last thing, make sure it's the street light. You don't want to use
up all your chances.
Best Wishes,
Michael C Martin
RFI Services
6469 Old Solomons Island Rd
Tracy's Landing MD   20779
301-855-5961 Tel
410-741-5153 Fax
21*29180 Nextel Direct Connect
mike at rfiservices.com

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