[RFI] RR crossing lights

Pete Smith n4zr@contesting.com
Fri, 20 Dec 2002 14:17:21 -0500

At 01:08 PM 12/20/02 -0500, Hare,Ed, W1RFI wrote:
>I recently designed and put together a mobile setup for measuring field 
>strength. (More on this later -- it is really slick!)  My initial setup 
>was on HF, to measure power-line noise.  I noted something interesting, 
>though. In some intersections, I am hearing a "tick tick" sound that 
>sounds just like ignition noise from an engine at idle.  It happened at 
>intersections where there were no other cars, though, and it didn't vary 
>with my engine speed.  I also noted that at one intersection, one and only 
>one of the LED lights was noisy, with about an S7 noise whenever it was on.

I'm not sure what the source was, but recently the local highway people had 
installed a portable light unit at a diversion around some 
construction.  The light unit had some sort of wireless sensor that seemed 
to detect whether there were cars waiting.  It, or something else 
associated with the light, made a substantial "white" noise in my car's FM 
radio whenever the light was red.  Just thought I'd mention that as a 
possible additional explanation for light-associated noise

73, Pete N4ZR
Happy Holidays