The batteries are about done with life. lol ASC's sirens pulse like that when they are running Undervoltage. FS and Whelen controllers just abruptly drop out when it happens to them.
Wow, that's interesting! I guess that's one good reason for a town to have ASC electronic sirens. That way, if one of their sirens were to produce a pulsing pattern on test day, that town would be notified that siren is not working properly and know why.
The batteries on that siren just died just the other day when a siren enthusiast was recording it for the monthly siren test. It couldn't even finish it's attack cycle, and then the batteries finally died.
