Memphis, TN
Memphis, Tennessee maintains a system of 109 outdoor warning sirens. They include Federal Signal Thunderbolts and 2001s, ACA P-10s, P-15s, and P-50s, ASC T-128s, a Whelen 2910, a B&N Mobil Directo, a Sentry 20V2T [needs citation] and a Darley Champion. Memphis is believed to have one of the most diverse operational siren systems in the country. The sirens are tested each Wednesday at 3:30pm in Alert.
History
The first siren installed in Memphis was the single tone Biersach & Niedermeyer Mobil Directo located atop East High School on Poplar Avenue, which still runs today. Originally powered by gasoline, the siren was eventually converted to run off of electricity.