B&N mobil directo

Intro The Mobil Directo was a rotational civil defense siren, made by Biersach & Niedermeyer Co. from the 1942 until 1967, and was the predecessor of ACA's popular Allertor 125. It was one of the first rotational sirens ever created, and boasted unparalleled sound output when it was released, and found extensive use throughout the United States and Canada. Three variants of this siren existed, the gasoline-engine driven BN52 and BN54, and the electric-motor driven BN44E. The original variant, the gasoline-engine driven BN52 (and later BN54), used a 25 horsepower, VF4 Wisconsin air-cooled, gasoline engine to drive the rotor/stator assembly while also rotating the entire siren assembly. This variant was initially produced for the U.S Army for use on remote island airbases in the Pacific Theater during World War II. In the 1950s, during the height of the Cold War, the BN52/BN54 were installed in several cities and towns throughout the United States. Approximately 2000 gasoline powered units were produced and sold until its discontinuation around 1953. All BN52 and BN54 units came exclusively in 8-port single tone, and were roughly 125db at 100ft.