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Electromechanical
The classic rotor & stator sirens everybody loves!
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Electronic
They're electronic speakers!
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Rotational
They rotate!
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Omnidirectional
They don't need to rotate!
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Have a...
Info
Civil defense sirens, also known as air raid or tornado sirens, come in many different shapes and sizes. There are 2 main types of civil defense sirens. An electromechanical siren is a siren that uses an electric motor to drive a spinning rotor, or chopper, inside of a stationary stator.
An electronic siren is much different than a mechanical siren. Rather than using a chopper, electronic sirens make use of a tone generator or stored preset sounds and amplifiers inside a controller, which broadcasts tones to the siren itself. Other types of sirens also exist, including friction, hand-cranked, and gasoline-driven sirens. Civil defense sirens are an important key in keeping the public safe from danger, alongside modern technology.
We have 183 articles, 1,396 files, and 13 active users. While we aim to stay factual in our information, we are not gospel. Information on this wiki can be incorrect, so don't refrain from doubting information and voicing your thoughts.
This month's featured siren...
The Model 500 is a series of midrange rotational mechanical sirens that was produced by Federal Signal, intended to provide a midrange option for cities who did not want to invest in the longer range, but more expensive and maintenance-heavy Thunderbolt. Unfortunately, this led to the 500 series being overshadowed by the Thunderbolt series and increasing failures of the 500's rotators have led to it becoming rare after its discontinuation in 1981.
The 500 series was introduced in 1953 and advertised as a midrange alternative to the then-new Thunderbolt siren. The 500 could output significant noise without a blower, which made it simpler to maintain. There were three models introduced in 1953: The 500-SH, which made use of Federal's C3 1/2 Model 5 or STH-10's rotor and stator, and came exclusively in 8 and 12-port single tone, the 500-SHTT, which came in 9/12 port dual tone and made use of Federal's SD-10's rotor and stator (and is sometimes also referred to as the 500T), and the 500-DHTT.Early 500 series sirens came with larger motor covers, and a much shorter, wider projector horn that was at a steeper angle than later generations. These horns are the lower halves of an SD-10 repurposed into a horn. Some of these early 500 sirens came with reinforcing bars in the horn, which would stabilize and reinforce the horn as they were prone to warping. Most of these are 500-SH units, with few 500-SHTT units having these reinforcements. All 500 series rotators (minus the 500-DHTT) are belt driven by the chopper motor, using a belt connected to a gear reduction drive, which then drives another belt below the motor which rotates the horn and motor assembly above the stationary rectangular collector ring housing. Many examples of these early 500-SHTTs can be found around Los Angeles, CA, as part of its decommissioned civil defense system. 500-SH and 500-SHTT sirens both came with 10 hp dual-sided motors, in 1 ph (208 V) or 3 ph (220 V/550 V, similar to CLM sirens) AC power. (Full article...)
Previous featured siren: • Julius Pearse Fire Department Supply Co.
Did you know...
- ... that the Chrysler Air Raid Siren originally began as an experimental siren created by the E.D. Bullard Company and Bell Laboratories?
- ... that despite its name, the ASC T-128 actually outputs 129.5 dB at 100 ft?
- ... that I'm Jim Biersach, president and general manager of Alerting Communicators of America?
- ... that friction sirens were once common until exploding rotors led to driver injuries?
- ... that the oldest known dual tone siren still in existence is an 8/16 port Inter-State "Long M" located in Dolgeville, NY, dating back to 1912-1916?
(More facts...)
About
Welcome to the Civil Defense Sirens Wiki! This site is dedicated to providing a factual, informative database about civil defense and tornado sirens across the world! If you have good knowledge about a siren and/or series of sirens, feel free to contribute! Everybody is welcome here!
Please add and share your knowledge, but vandalism and unwanted edits may lead to consequences. If you have any problems, leave a message on one of our admins' talk pages. Note that this wiki is for real, legitimate siren information. However, you're welcome to post fan-made materials on the Fictional Sirens Wiki. We also ask you to read the Rules and ask for some advice before writing a page, so you can avoid having your page deleted. You can ask for feedback from your page in the discussions, and you are free to ask any questions. Enjoy your time on the site!
News
07/2/2024 • Articles for a wide variety of non-American sirens are currently in the works! Check out our Elektror, Lion King, and Engesig articles to broaden your siren knowledge! In addition, a new page has been created for sirens which do not warrant their own articles but are worth mentioning, which is our miscellaneous sirens section!
In other news, the 6th round of the 2024 Monthy Featured Siren Vote has ended! We got 7 votes! The winner was the Federal Signal 500, with 5 votes, while the ACA Penetrator series got 2 votes. In addition, congratulations to trainsarethebest_alt for winning this month's featured artist! Anyone who wishes to submit photos for next month's featured artist can do so on our Discord! Thank you to all who voted!
Featured Artist
Status: Inactive?
Use: None
Notes: Bee and Emm. 'Nuff said.
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Links
Sister wikis - Contributors welcomed!
- Siren Systems Wiki - Articles about existing siren systems. More articles are very much wanted!
- Fictional Sirens Wiki - Get creative and share your custom/fictional sirens and companies! Anything goes. *Please note that the "Sirens That Do Not Exist Wiki:" has been abandoned and this is the replacement site.*
- The Crossing Signal Database - An under-construction wiki dedicated to railroad crossing signal equipment, such as bells, lights, gate mechanisms, and more! Help is very much wanted.
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