Woolridge wrote:

http://www.freep.com/news/statewire/...4_20040108.htm


In Nebraska, my hometown use to activate the tornado and civil
defense sirens using a series of tones that were transmitted over
the regular police channels.

I built a small 10 milliwatt transmitter to that frequency, recorded
the tones when they tested them, then would drive by a siren and play
back the tones. Sure enough, I could set off the tornado sirens.
Not city wide, of course. People sure would come out and look around
when the tornado sirens were going off in January with snow coming down.