The old telephone systems relied on a closed contact to start the sirens. You basically had two wires, one of them had power on it all the time. The other one was dead until the switch was closed, completing the circuit. If you shorted those two wires together anywhere you completed the circuit, an...

Here's a very sad condition Thunderbolt 1000T behind American Legion post 29 in Marietta, GA (Cobb Siren 31). Only the chopper works on this old T-bolt. Who knows when this thing was put up... http://farm8.staticflickr.com/7074/7331283294_3f8d96964f_c.jpg This siren was in place when I moved to Cob...

A very healthy sounding siren. I've observed it in action a couple of times from either the Walgreen's or the shopping center across Moore's Lane from Walgreen's. I believe the Holly Tree Gap Rd. siren can be faintly heard in the background. One thing different I noticed about this one. When it stop...

I believe that Emory Tbolt was either at or near the intersection of Fishburne and Clifton.

There definitely was a Tbolt on the Emory campus. I saw it a few times. I'm pretty sure it was somewhere along Fishburne; just not exactly certain of location.

I lived in Cobb County from 1971-1989, but was in DeKalb on numerous occasions. I'm familiar with some of the sirens Brendan mentioned in his original post. The ones I saw the most were I-85/Chamblee Tucker. Lewis & Litton, & Briarcliff/LaVista. There was one somewhere in S DeKalb(other than...

I saw a lot of the San Francisco ATIs when I was there in summer of 2011. Some of them are mounted rather low. I recall seeing the one at Union Square; I was on upper deck of tour bus. Could almost stand up and touch the siren. I also saw one atop a building, but don't recall where it was.

A few more comments on Cobb County system. #27 has been moved across the road from Macland Baptist Church. #1 replaced a Thunderbolt instead of SD-10. Smyrna has one siren not mentioned on the list. It's on Pebblebrook Rd. near Vinings Estates Rd.(or Dr.). I tracked it down once..that siren is almos...

Great Cobb County Map! I didn't know there were so many sirens on the Dobbins complex. Some comments about other sirens. Cobb #3 replaced a Thunderbolt which was originally at Cobb FS#3 on Terrell Mill Rd. #37 also replaced a Thunderbolt. I believe that #43 was taken down due to road construction; #...

Nashville did a good thing with the new system. Most of the system is Eclipse sirens; I believe 19 of the sirens are 508s. Both have a great sound. Is it an echo or do I hear another siren(possibly the Coley Davis Rd. one) in background of this video?