In Reply to: Crosswalk signals / school zone signals posted by CraigH on September 05, 2000 at 10:05:29:
: Has anyone else noticed the new crosswalk (intersection) signals and school zone signals with a 19" whip or rubber duck antenna on top of them ? Anyone have any info on these devices or the freqs they operate at ? Are they RF switched or is it feedback data ? The school zone signals that I am refering to had a large solar panel attached, . . . probably battery operated ?
These signals probably use freqs in the 20-50MHz range to receive short data bursts telling them to turn on or off.
zach