The Siren Board

Here's a picture of a Mobil Directo I can contribute. This was taken in Atlanta, Georgia in 1974. I have a thread on Atlanta's CD system that has several more mobil directo pictures in it, this is one where the siren is clearly seen though, hence me contributing it. And no, this isn't my picture. All credit to the original owner.

That's a nice photo. It shows how high-up some of these sirens were in the bigger cities.

Other then the remaining siren on Green Tree and the one that was salvaged near the Marquette Interchange does anyone know the original locations of the Mobil Directos in Milwaukee?

Here are a few locations.

Jones Island had an electric Mobil Directo. It was destroyed by a lightning strike and was scrapped in 2011. I think this one was dual tone, so it would have been a later addition. It is on the siren archive - you can barely make out the Mobil Directo platform and motor frame. http://www.jmarcoz.com/sirens/milwaukee6_wi.jpg

Wauwatosa also had a Mobil Directo mounted on the East high school at Wauwatosa and Milwaukee Avenues.

Outside of the Milwaukee 'burbs, there was a gas Mobil Directo in Janesville, WI. This one was mounted on the city hall near the Rock river. It was withdrawn by 1960.

Here is the 2009 street view of the Jones Island Mobil Directo. It appears that in 2011 Veolia water did some construction by the building where the Mobil Directo was mounted. I believe that the siren was removed with the tower during construction.

https://www.google.com/maps/@43.01962,- ... 312!8i6656

(The siren is to the right of the yellow crain)

Thanks for the Google Streetview link. My notes from Milwaukee County EMA stated that the Jones Island siren was taken down in late 2010 after it was destroyed by a lightning strike - the damage was too excessive to consider repairs. The siren and its tower were taken to a local contractor who scrapped them in 2011.

A T-128 replaced the Mobil Directo, however it was mounted in a different location.

Were these sirens sold with 9/12 port configurations? User ECwindsor posted some pictures from a newspaper with what seem to be 9/12 port variants of these sirens with 3 vanes instead of 4.
https://www.airraidsirens.com/forums/vi ... =2&t=17958

No - all Mobil Directos were shipped out as 8 port (BN44-G) or 10-12 port (BN44-E). The four rotor blades are pressed in place during manufacturing. It is possible that a different set of blades were temporarily used, however every example I've documented used the standard four blades. The blades draw in air - while many sirens have the blades positioned to align with the rotor ports, this is not always the case. Blades that cross over any of the port openings will give a warbling tremolo effect, as noted in my first post.

SuperBanshee wrote:No - all Mobil Directos were shipped out as 8 port (BN44-G) or 10-12 port (BN44-E). The four rotor blades are pressed in place during manufacturing. It is possible that a different set of blades were temporarily used, however every example I've documented used the standard four blades. The blades draw in air - while many sirens have the blades positioned to align with the rotor ports, this is not always the case. Blades that cross over any of the port openings will give a warbling tremolo effect, as noted in my first post.

So the gas powered kind were single tone and the electric were dual? Or did I misread your post?

coastalsyrolover wrote:

SuperBanshee wrote:No - all Mobil Directos were shipped out as 8 port (BN44-G) or 10-12 port (BN44-E). The four rotor blades are pressed in place during manufacturing. It is possible that a different set of blades were temporarily used, however every example I've documented used the standard four blades. The blades draw in air - while many sirens have the blades positioned to align with the rotor ports, this is not always the case. Blades that cross over any of the port openings will give a warbling tremolo effect, as noted in my first post.

So the gas powered kind were single tone and the electric were dual? Or did I misread your post?

I think so. Not exactly sure though. Here is a link of the video.

https://www.youtube.com/watch?v=dSj-7TCelro . This is an 8 port Mobil Directo that is located in Milwaukee that was gas powered. Then when ACA refurbished the siren, they swapped out the old motor for a electric one.