I was in Bristol/Tri Cities area for a funeral this April and saw a 500 series still up.

https://goo.gl/maps/ic3k7va5gcB2

You seem to be correct!
Photo credit to the source.

That sucks, but such is Island life. Luckily, HI will always have multiple needs for outdoor warning sirens, and I think we can expect to see Modulators for many more years.

So interestingly enough, and many people know this, the very first conceptual 2001 looked a LOT like an RSH-10. If these sirens [Tbeams] weren't so inefficient and had suffered fewer problems with their rotation design, I think they may have lasted awhile longer. Is that the prototype 2001? Or is t...

There are still quite a lot of 1212/612 and first generation Modulators on the Big Island. I've been going there twice a year for the last 3 years now, and the replacement process is a very slow one. The only huge changes have been the SD/STH-10's coming down and the upgrading of the controllers on ...

So interestingly enough, and many people know this, the very first conceptual 2001 looked a LOT like an RSH-10. If these sirens [Tbeams] weren't so inefficient and had suffered fewer problems with their rotation design, I think they may have lasted awhile longer.

I think the actual rotor/stators on these are Denver products. Sterling may have sold them paired to motors as their own, or on behalf of Denver. Note the term "Quadruplex" on the advertisement. That is definitely a Denver term, not Sterling's.

It's on the 'hit' list I am sure. I think this is the only electronic siren left in the system. All of the Modulators have been removed--they were actually the first to go. The other AL-4000 that was having issues a few years ago was actually swapped with a 2T22.

Also, the town of Quanah, TX insists both of these sirens are still in use. We have emailed a couple of times. This is probably one of my favorite setups, and I hope to one day get footage of them both sounding.

Savoy, TX has a triple. Not exactly sure on the order, or if both 3V8's are still in operation, but I imagine the 2HP isn't used much anymore.