Aloha fellow siren enthusiasts! Here you will find a good mix of electromechanical & some electronic Federal Signal sirens around Oahu.

About Oahu Civil Defense sirens: We're strictly a Federal Signal state (no other siren brands here... FOR NOW: that will change in the future: ASC coming...)

Tests are held at 11:45am on the first working day of each month. A good majority are still electromechanical sirens like Thunderbolts (plenty of high pitched 1000Ts), ST(H/L)-10s, SD-10s, a few RSH-10s, and some 2T22s. Sorry, no 2001s, 1003s or 3T22s here.

Electronic sirens are becoming more common here since the Oct 2006 quake knocked the power out for the whole island of Oahu, rendering the electromechanical sirens useless and silent. Battery backup+solar powered Modulators and DSAs are slowly replacing the electromechanicals. Most, if not all, Modulators & DSA's are dual tone and sound pretty good.