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controls?
Posted: Fri Nov 17, 2006 8:48 pm
by pyramid head
do all sirens have control boxes? and can you make the calls longer/shorter if you want?
Posted: Fri Nov 17, 2006 10:57 pm
by AllSafe
Not all sirens have control boxes. Some small systems, like the one northwest of here in Haven, are controlled by 24v lines which just switch a motor starter.
Posted: Sat Nov 18, 2006 2:13 am
by Justin
Most, if not all newer systems will most likely have control boxes of some sort.
These controls will have an encoder/decoder for DTMF, communications equipment (if activated by phone or radio communications) then the bells and whistles that control the siren itself; things like motor timers and voice communication circuits (electronic sirens only).
By calls, do you mean DTMF tones? As mentioned before, you can change the length of a DTMF communication.
Smaller sirens and most older systems (unless the local EMO decides to upgrade their older sirens) would not have controls (or modernised ones). Smaller sirens usually have a flip switch at their installation (ie. Fire stations) and the cold war sirens would have the really old controls.
Posted: Sat Nov 18, 2006 2:50 am
by pyramid head
what signals cana sterling m do?
Posted: Sat Nov 18, 2006 3:47 am
by Trey
pyramid head wrote:what signals cana sterling m do?
Alert and Attack as far as I know.
I don't remember if some came with shutters or not.
Posted: Sat Nov 18, 2006 7:53 pm
by pyramid head
and are the sterling's omni or uni directional? i see they ahve two projectors but does it rotate to?-also im looking for a pic. with a weird looking siren that looks as if there are about 3 2t22's stacked on eachother. i saw it a few times but now i cant find it a gain!
Posted: Sun Nov 19, 2006 6:51 pm
by Daniel
I have never heard of a rotating Sterling. They came in single tone (usually 16 ports, very high pitched) or dual tone (8/16 octave just like modern Sentry 20V2T's). They are omnidirectional, but the sound output is naturally more concentrated in the direction of the ports. Horizontal sirens relied on a theory of sound refracting off of structures as a means to carry the sound. Many of them are mounted lower for this reason, especially in the UK. Sterlings that had a code function used a brake rather than shutters like a Klaxon. These sirens are easy to spot because the cowling over one rotor is longer than the other.
Here is my YouTube recording of a single-tone Sterling M-5 from the late 1920's (read the notes about the curved pipes):
http://www.youtube.com/watch?v=erW7nwpvZqo