The Siren Board

According to Steve, this is the UK four-tone siren! Plus notice a single tone siren on the floor.

Probably no chance of ever getting a hold of one of those French sirens someday unless they are auctioned off...they are property of the ministry of war.

Way back in your first post you mentioned a network of sirens in Portsmouth. That's not something I was aware of and it's not too far from where I live. Do you have the locations of any of them so I can go and get some pictures? I'll post any I get.

Thanks very much.

That isn't a four tone siren. Look at the port spacing. It just has 2 rotors of the same dual-tone interval. Innovative though.

It looks to have an eight-to-twelve port ratio. Very interesting indeed, though not too efficient. 8)

No, it is a three tone siren. The inner rotor sections are the same, but the outer rotor on the right side has more ports that the other outer rotor. It appears to be 10/12 and 10/14. This would generate the approximate notes of Bb/Db/E, or Bb diminished. I would love to hear that! That siren on the floor looks something like a Federal Model 7 low tone siren.

My apologies - I was going by memory from my childhood. I didn't have any pics so assumed that when I'd seen two sirens with 4 rotors they must've been with four different tones. Hi Andrew - yeah there's a siren network in Portsmouth to let the Dockyard and surrounding residents know that they might have to take their potassium iodate tablets. Unfortunately, all the sirens are within the confines of the Dockyard itself so getting near to the sirens is difficult. However, I do have some photos on my friends camera I can post from when I went into the Dockyard. They have about four or five sirens.

No apology necessary, as it is much easier to count ports on a photograph of a siren sitting on a table in a museum than one on a pole inside a restricted area. Do you know whether any sirens like this are still in use?

I believe there still might be one on the side of the control tower at Hurn Airport (way off from public access I'm afraid). It was a bright yellow 'Crash Siren'. I'm going to write to them to see if they'll let me back onto the airfield. I used to go flying there and was once in the tower only a few inches from the siren switch. Was v tempting and hard to resist setting it off. That's assuming its still there (it was a few years ago), but if it was still working I'm guessing there wouldn't have been a need to replace it (it did look very well maintained). And if its still there then it must be tested from time to time.

I'd be really interested to see the Portsmouth dockyard sirens. Please post them if you do get a chance. I decided to do a bit of research and I came across this information about Portsmouth siren tests. It seems they're tested on the last working days in February, June and October.

http://www.royalnavy.mod.uk/server/show/ConWebDoc.5997

Next week then.... Shame it's a work day - I'm a bit too low on holiday to be able to go. Maybe February...