At 5,000 pounds each, it looks like they were Victory sirens:

https://www.newspapers.com/article/the- ... 125059378/

A single tone Thunderbolt at 28:30 here:

https://youtu.be/To9wCzLMqCw

Most of the sirens around San Jose have the control boxes mounted like this.

San Jose Calif. has some sirens near schools:

https://goo.gl/maps/s6EqkurYo8BDA1eQ7

https://goo.gl/maps/8ezvCgvaRYkw37Jm9

https://goo.gl/maps/FthqANz8ZBjq9wSp6

Which map did you use?

Back in 1976, the San Jose City Electrician was nice enough to give me a copy of the list of San Jose siren locations. I sure wish I could find that now.

There are a variety of frequencies that could be used, like anywhere on the Public Service bands: 30-50 MHz 150-172 MHz 450-512 MHz 700 MHz 800 MHz They might be using a Public Works frequency, for example. And, some places use frequencies that they don't have an official FCC license for, so referen...

I don't know if anyone has shared this before, but I'm amazed at the number of sirens heard in this one:



https://www.youtube.com/watch?v=cP-7NISM2nI

I just found a old newspaper piece that mentioned the cities that used Chrysler Victory sirens:

https://www.newspapers.com/clip/1100846 ... ry-sirens/

2 tone Screamasters in Sacramento:

https://www.newspapers.com/clip/107788968/

Long Beach CA Screamasters:

https://www.newspapers.com/clip/107789099/lb-sirens/

The firm that manufactured Screamaster sirens is Robert J. Zievers Inc. They also made frost protection windmills. The 25th Anniversary of Screamasters in Sacrament CA: https://www.newspapers.com/clip/107787866/ La Verna CA Screamaster: https://www.newspapers.com/clip/107788224/la-verna-screamaster/...