The Siren Board

Who posted that 30 ft long horn on top of this one building in the old forum? It looked like a giant yellow musical horn. Was it a really odd looking siren or just a decoration?

Do you mean the picture that was posted a couple of weeks before the old board closed down? If so, I can definitely say that with its large profile of the horn, this thing won't go anywhere if it is powered by a casual compressor system. It could be a siren, though.
I remember that it was Adam Smith who posted the picture, so I think that he might know as to where it is.
Some people even accounted it for a microwave-projector, for communications.

Here is the page with the photos of that siren - or whatever it was! Go forward a few images to see both of them. The second one is very odd-looking.

My earlier speculation was that they're microwave horns of some sort, or perhaps accoustic sensors. But they look rather foreign compared to even the oddest microwave horns I'm used to seeing.

They're both pointed at downtown Toronto, if that provides any clue.

Really. I took a vacation in Toronto this year, and didn't see any horns of the big yellow variety!

Somebody has to geocache this thing. It's big enough it ought to be visible on Google Earth if it's an area with high-res imagery.

Here is mystery siren/horn's cousin.
http://www.flickr.com/photos/admitone/89040787/

This one must most definitely be a microwave-projector, because there is no air-intake.

I've never seen those a day in my life and I've been all over Toronto. All I've ever seen is Allertors and CMS sirens around the city. Someone should email all outlying counties of Toronto to find out what it is and what its used for. I'm not going to do it myself, but if you are interested...

Regional Municipality of Peel
Regional Municipality of York
Regional Muncipality of Durham- installing ATI's as we speak.
City of Toronto

They'll have websites on Google.

Is this the one you're looking for?