The Siren Board

I've never heard an STL-10, but have seen a couple.

Several years ago I noticed one atop a building in downtown Jackson, MS.
It was painted yellow. I'd been in Jackson for a convention; spotted the siren while riding shuttle back to the airport.

I also saw a red one somewhere in PA the next year. It was mounted on a platform between two poles; rather low; right near the side of the road.
I'm not sure just what city/township it was in. I was with group on a bus going to an event somewhere outside Philadelphia.

As others have mentioned, the STH-10 has 12 ports. It has the 12 "megaphones" around its circumference; the motor sits atop the siren.

I've made the observation on this board that the STH-10 is my 2nd favorite siren after the Thunderbolt.

The city of Smyrna, GA(where I used to live) began installing a tornado warning system about 30 years ago. Initial installation was 4 or 5 STH-10s; over the next several years it was expanded to 11 of these sirens(system also has 3 Whelens and 2 of the old DeKalb County, GA thunderbolts).

Smyrna used to test the sirens every Saturday at noon. I thought the STH-10s had a great startup sound; they took a long time to wind down.

The sirens are still in place(I visit the area twice a year) and to my knowledge are still sounded for tornado warnings.

Yes. Special Tone High has 12 ports/cones, (694 Hz note F5) though from the name I'd expect 10 cones.
Does 10 mean horsepower?
SP Low has 7 ports/cones (405 Hz, note G4)

Must be quite a dissonant sound from notes G and F above.

Robert: I believe that STH-10 used a 10 HP motor. Don't recall if I read that in a Federal brochure or just where I heard it.

Even though STH-10 is a single tone siren, it has a good sound. The tone carries well; often beyond the estimated 1/2 mile radius.

I could hear the one at the Smyrna Police Station siren(about 4 blocks away) inside my house with the windows closed.

One of my friends delivered mail from the Smyna P.O. I remember him telling me that he heard the siren many Saturdays, even though he was several blocks down the street from my house when it sounded.

When the 30 second test ended..and the sirens shut off..I could hear 2 more of them winding down.

The EMA director told me that he really wanted to get Thunderbolts. However, due to price constraints, the city was able to get more STH-10s for the available funds and cover more territory with them.

The STH-10 is a real workhorse..good siren.

At 10 hp, I'd expect it easily to be heard further than that, especially the lower 405 Hz STL-10.
Is the STH half of a 2t22?
But 2t22 has two sirens on one 10 hp motor.

The 2T22 and 3T22 sirens have rotors the diameter of the rotor of a Model 3. The STH-10 sirens have a pretty big rotor, giving them the long wind-down.

Those are my two ideas for the STL-10 cover/housing

Ok, today I took a picture of the STL-10 near my town!

pyramid head wrote:Ok, today I took a picture of the STL-10 near my town!

Meh I live closer to one than you think and it's weird when the Modulator siren goes off.

Btw I heard this siren up close before and I took this picture a long time ago...

^Upper Yoder Twp. VFD^
PS. I'm back from from my break.

This one was installed a couple of years ago in Lincoln City, Oregon, as part of their tsunami system. I don't know where they got it, but it replaced an STH-10 on the old station a couple of blocks from here. All their sirens are painted blue except the stainless steel Model 5 on the other fire station and the brand new 2001 a mile south of this one.

I do not know where I read this, but I think somebody said that STL-10's were made for mountainous area's, and the low tone is for penetration. Is this correct?