Found a really good video of the old grid-faced Thunderbolt 1000A mounted up on the side of a cell tower, right outside the South Shades Crest Elementary School property. The siren sounds approximately 1 minute each of alert and attack, for the monthly Jefferson County siren test. Seen this siren several times before, but I never knew it had the grids in its horn since it was always facing away from the road.
http://www.youtube.com/watch?v=K7GiKRFunPY
Location:
http://g.co/maps/y3xr3