Sorry for the late reply but the type of air raid siren that was atop Houston City Hall & other locations throughout the city was a "Thunderbolt" supercharged electro-mechanical siren made by the siren manufacturing company Federal Enterprises (now Federal Signal) of University Park, IL. Many municipalities across the country had these from through the mid 50- early 80's as Civil Defense sirens but most up today are in the Midwest and used as tornado sirens. Thunderbolts were capable of producing a sound output of 126dB or higher from close range and had an audible radius of up to a mile away from the siren. However, the single tone variants of the Thunderbolt made a very similar sound to a Chrysler. The siren was removed from the city hall back in the late 80's but others are still standing abandoned in place at the following locations:
* JP Henderson Elementary School
* Burnet Elementary School
* Northline Park
* Two along the refineries along Buffalo Bayou
* Blodgett St & Ennis St
* Denver Harbor Swimming Pool.
Other communities in the Houston area such as Friendswood, Pasadena, Deer Park, La Porte, Baytown, and Texas City have sirens in place used to warn of chemical spills from nearby refineries and are tested regularly. Here is a list of their siren testing times:
La Porte & Deer Park: Saturdays at Noon
Baytown: Wednesdays at 9:00 am
Texas City & LaMarque: Wednesdays at Noon
Mont Belvieu: 1st Wednesdays at 4:00 pm
Pasadena: 1st Thursday of every month at 6:00 pm
Friendswood: 1st Friday of every month at Noon
Hope y.all can find this information helpful :)
