When were air raid sirens made?

Answer 1

Although mechanical sirens existed before the 1900's, Federal Sign and Signal Corp (then Federal electric) purchased the patents for an electronic siren in 1915. A common purchaser were coal miners used to warn of a disaster. By World War 2 many municipalities purchased them to warn in case of air raid. However, not all locations had electricity, so the search was on to find a non-electric siren. Chrysler corporation, was a big war time supplier created what it called the "victory siren". Powered by a hemispherical engine ( a hemi ) to date it is the loudest siren ever produced providing 138db (loud enough to cause ear damage) and could be heard a mile away

Answer 2

jim the boy