As many of you know, Schenectady County has a diverse system; unfortunately many sirens are inactive, but those are in the city. So, to make things easier, I'm going to go in chronological order:
Starting in the earliest times, the Rotterdam Fire Department purchased a Sterling Y-10, in 8/16 port combo, presumably for fire calls. It is still used today, and sounds daily at 6 PM and for fire calls. It is unknown if the coding mechanism is used, it most likely isn't. Also, the Scotia Fire Dept. has a Sterling M which is probably used as well with the Diaphone there.
I also have a suspicion that Quaker Street Volunteer Fire Department had a Sterling, as they are the most common "old fire sirens" in the area. Not only is their Model 2 newer (mentioned below), but there is an old, rusty stand with an access ladder across the street from the FD, so I'm guessing for that reason that a Sterling was the previous siren (I'll try to ask them in a not-weird way).
During World War II, the City of Schenectady may have purchased Chrysler sirens. I know it sounds absolutely ridiculous, but when Daniel pointed out that the Thunderbolt on 1237 Albany St. (mentioned below) has a huge platform that a Chrysler could fit on, and the fact that Schenectady was most likely a key target area for destruction due to war production there, it would make sense.
After World War II and into the Cold War, Schenectady County had purchased 10 SD-10s by 1964, along with 4 in the city and 4 Thunderbolts in the city as well. These were most likely purchased in the early to mid 1950s, as the Jailbar Thunderbolt on 1237 Albany St. has completely lost its paint. Also, it looks to be a 1954ish model because of this. This system was in place for a long time, and ran on a certain Saturday at noon. This went on until perhaps 2005(?) or even earlier than that. I remember hearing an SD-10 going off at noontime for one of my youth football games; if memory serves they went in Alert first, then maybe a pause, then Attack. Sometime in the 1960s or so, Schenectady tried to purchase 5 non rotating, 10-horsepower sirens. Knowing that in general, New York is a strict Federal Signal buyer when it comes to sirens (Sterling/Sentry is 2nd), I'm guessing they were 500s. Wether they were purchased or not is unknown, but it appears that if they were, they no longer are up. Nonetheless, an organized, county-wide system is no longer in place; however many sirens still stand, unused. It should be noted, though, that some sirens are used for fire; and those even double as severe weather sirens. The future of the old system is questionable; it may stay turned off for the time being, but tornadoes and other severe weather are becoming more frequent in the area.
As of 11/21/14, the old system was offline.
Now, here is the current list of sirens in the county of Schenectady. A * next to a siren means it is inactive; a (?) means it is unknown if it is still in use:
- 1 ) Federal Signal 2001-SRN (DC): Delanson Fire Dept., Main St., Delanson
2 ) Federal Signal Model 2: Quaker Street Volunteer Fire Dept., Quaker St., Delanson
3 ) Federal Signal STL-10A: Duanesburg Volunteer Fire Dept., Duanesburg
4 ) Federal Signal STH-10A: Pine Grove Fire Dept., Rotterdam
5 ) Sterling Y-10: Rotterdam Fire Dept., Rotterdam
6 ) Federal Signal STH-10A: Rotterdam Junction Fire Dept., Rotterdam Junction
7 ) Federal Signal STH-10A: South Schenectady Fire Dept., Rotterdam
8 ) (?) Federal Signal STH-10A: rail yard next to South Schenectady Fire Dept., Rotterdam
9 ) Federal Signal STH-10A: Rector Fire Dept., Rotterdam Junction
10 ) (?) Sentry 5V/3V8 (unknown which): Route 8, Rotterdam Junction (Red; implies it is/was a FD siren)
11 ) *Thunderbolt 1000: 1237 Albany St. (former Freihofer outlet store), Schenectady (Tap 6)
12 ) *SD-10: Schenectady City Hall, Jay St., Schenectady
13 ) *SD-10: Rotterdam City Clerk, Vinewood Ave., Rotterdam
14 ) *SD-10, (?) Sterling M-10, (?) Gamewell Diaphone, Model A/D: Scotia Fire Dept., Scotia
15 ) (?) SD-10: Niskyuna Youth Football Field, Niskyuna
16 ) Mystery Siren: Niskyuna Fire Dept., Station 2, Niskyuna (10 port siren; looks like a vertical Sterling/Model B type of look)
17 ) STL-10A: Carman Fire Dept., Carman/Rotterdam
Thunderbolt 1000 (Albany St.):

*My picture
SD-10 (Schenectady City Hall):

*NOT MY PHOTO*
Schenectady newspaper with "CD Siren Effectiveness" cutout on it:
http://news.google.com/newspapers?id=5c ... =html_text
Schenectady newspaper article with the discussion of the rotational sirens mentioned above:
http://fultonhistory.com/newspaper%208/ ... 204448.pdf
Schenectady Civil Defense drill video:
http://www.cbs6albany.com/contact_us/fe ... html?wap=0
Another newspaper on Schenectady's sirens:
http://fultonhistory.com/newspaper%208/ ... 202224.pdf
A (rather funny) story on an accidental siren activation:
http://books.google.com/books?id=rROoJm ... CDIQ6AEwBw
Whew! Biggest post I've ever made! Thanks for those who cared to read.