AirRaidSiren Wiki
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The CLM air raid sirens were produced during the 1960s for Canadian use during the Cold War, by a company known as Canadian Line Materials. Little is known about these sirens due to their rarity and lack of information.

The CLM Rotating Siren is a 5HP rotating electromechanical siren, and is largely a CLM Carter siren with horns and a rotator. It is 10/12 port, with the 12 port being dominant due to its design. It appears that the siren was originally intended to be 12 port single tone, however the Canadian government dictated it to be dual tone, so the 10 port was added on as an afterthought. The 10 port side has only 3 ports on the stator, with a 10 port rotor. The rotator is powered by a separate motor, with two belt driven pulleys and a gearbox rotating the siren at approximately 12RPM, far faster than most rotating sirens. This causes the siren's sound to "waver" significantly as it rotates.

CLM Carter

A CLM Carter siren.

CLM also offered other siren models. There was a 5HP vertical omnidirectional siren with a large intake on top, which was also 10/12 port. These are very, very rare, with only 2 known to exist. CLM also offered a rebrand of the British Carter siren, being a near duplicate but running at 60hz power. Finally, they also offered a 20/24 port Carter style siren, with much larger rotors. These run at half the RPM of regular CLM sirens, which causes them to sound like a slightly higher pitched 10/12 siren. CLM also produced other variants of the Carter with different sizes.

CLMS were installed across Canada during the 1960s, especially in larger cities like Toronto and Ottawa. After the Cold War, all of these sirens were decommissioned as there was no more use for them. As Canada doesn't get severe weather like tornadoes often, sirens don't have much of a purpose. A few of them still sit on top of poles and rooftops, rotting away, while others have found their homes in museums and private collections.

Omni CLM

A vertical CLM omnidirectional, one of two known to exist. In private collection.

20-24 CLM

Two 20/24 port CLM sirens, both privately owned.

Weird CLM

Another CLM Carter style siren, with much thinner rotors and a different motor.

A few CLMs have been refurbished and put back into service as fire sirens. These include units in Port Lambton and Alvinston, ON (Both 20/24) and a rotational CLM in Alliance, Alberta.

There is also a CLM siren in the town of Deer Lake, located above the main damn, the siren according to siren enthusiasts is apparently one of the Carter 10/12 copies Video of the CLM siren recorded by someone on Youtube

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