When I was growing up ('50's) we were in the "Cold War" and not only did we have regular practices in school with the bells going of in a horrid series of short rings (1 second on, one second off for one minute!) so we could dive under our desks to hide from the atomic bombs (uh-huh), we had city-wide "Air Raid Sirens."
The closest to my home was about 200 feet away, and was easily visible from windows on that side of the house. It was a huge, massive "thing" at the top of two "telephone poles" at the end of the alley.
Every week, for over a decade, those things went off at 2PM Wednesday for one minute. To the absolute best of my knowledge they were never actually USED for anything other than checking one's watch every Wednesday ...
Good luck with your new sirens, FC. You'll need it.
Take care,