That's the exact siren I recorded, on the exact same day, same location. The mystery of the unknown siren enthusiast has been solved. Originally I pondered who this guy was in this topic:
http://airraidsirens.com/forums/viewtopic.php?t=1725
maybe we can collaborate next time so we don't end up recording the same siren
my version: as many of you have repetitively seen already
http://www.youtube.com/watch?v=v2wsgI3w1CQ
here's a better picture from this guy's vantage point that I took the day before the test date.