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Rumbler siren. A Rumbler siren is a type of emergency vehicle siren used primarily in the United States.Developed in 2007 by Federal Signal Corporation, and sounding at a low-frequency level, it is designed to be heard by motorists who may otherwise be unable to hear high-frequency sirens due to ambient noise, such as urban traffic.
In a pneumatic siren, the stator is the part which cuts off and reopens air as rotating blades of a chopper move past the port holes of the stator, generating sound. The pitch of the siren's sound is a function of the speed of the rotor and the number of holes in the stator. A siren with only one row of ports is called a single tone siren.
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A civil defense siren is a siren used to provide an emergency population warning to the general population of approaching danger. Initially designed to warn city dwellers of air raids ( air-raid sirens ) during World War II , they were later used to warn of nuclear attack and natural disasters , such as tornadoes ( tornado sirens ).
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By this time, it made outdoor warning sirens, police sirens, fire alarms, and outdoor lighting. By 1961, Federal Sign and Signal had gone public, trading on the NASDAQ market. This was when new products started being manufactured and sold, such as the Federal Signal STH-10. In 1976, the company became Federal Signal Corporation.
A fire truck running the E-Q2B siren. Today Federal Signal's Q2B siren is still in wide use. The majority of users of the Q Siren are fire departments, although some ambulances and heavy rescue squads have employed the Q-siren. The Q-siren produces 123 decibels at 10 feet (3.0 m) with an operating current of 100 amps at 12 V DC (1.2 kW). [1]
UK, derogatory name referencing the modern police uniforms and armed squads of Italian Fascists under Benito Mussolini. Blues and Twos UK, from the flashing blue lights and the two-tone siren on a police car. Blueband UK, from the blue cap-band worn by PCSOs. [citation needed] Bluebottle Antique name for the police referring to the old-style ...