File:Finding the 13 Broadmoor sirens. Siren E - Crowthorne

Description
Our siren hunt continues in Crowthorne - 5 of 13 sirens (I've labeled them from A to M)

BTW - apologies for keep calling them "air-raid sirens". These are ESCAPE SIRENS.

Broadmoor currently have 13 escape sirens located in the neighbouring towns surrounding a secure hospital in the UK. Me and Chay went out to find them all - it was a very interesting bank holiday Monday lol! Chay was a bit apprehensive while waiting for the first siren to sound, but loved it afterwards :) He liked it enough to stay with me whilst tracked them all down.

It was a good day as we did other things like play football in the parks, McDonalds and see the sirens of course!

It was a mixed bag - some viewable from the street, some hidden so much that you'd never know they were there (unless it went off!), some in council depots, compounds, parks and believe it or not - in the middle of housing estates metres from houses! (would scare the living daylights out of residents if they went off at 3am!) Some are in secure places with no access at all.

The sirens are tested at 10am each Monday.

I have recorded 6 of them in action which have already been posted on youtube. See the links at the beginning of the movie.

HOW THEY WORK: The Klaxon CS8 siren.

A 415volt 3 phase motor spins two rotors on either side. One rotor is for the high tone and the other for the low tone (the one with most holes is the HIGH tone). During the escape siren, the airflow is cut alternately to each rotor by a shutter on each end producing the distinctive high-low tones. I believe these are known as CODED SHUTTERS - hence the model name Klaxon "CS"8.

Both shutters are opened together for the all clear tone. You can just make out the high and low frequencies being produced together if you listen.