The Siren Board

Discussion of Outdoor Warning Systems
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PostPosted: Tue Aug 13, 2019 5:23 pm 
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Joined: Sat Mar 30, 2013 3:50 am
Posts: 1362
Real Name: Dennis Seldon
YouTube Username: DJ2226
Location: Columbus, Georgia
I present to you all a weeks worth of failures between Columbus, GA and ATL. :lol:


I haven't been recording as much in Columbus as I have in the past. With half the system recorded and plenty of videos of what the system sounds like, I haven't really been as interested in recording here lately. I do keep an eye on things however, and something I've noticed is that there have been sirens in the area that have been consistently getting stuck in full cycles of various tones, usually wail or air horn. The typical structure of our testing scheme is interesting. For those who may not know we test alert (for a tornado warning) for a minute, wail (formally for a thunderstorm warning, discontinued but still tested) for 15 seconds, and air horn (all clear) for 15 seconds. The test starts with a pretest message and ends with a post-test message. After being retrofitted with Motorola ACE3600 RTU's in 2016 the sirens developed an unusual behavior where they would get stuck running in various tones for full cycles of 3 minutes. At first the initial thought was that the sirens were experiencing radio failures, however they would do it every test and mostly get stuck in the same signal consecutively. I've boiled it down to the sirens' batteries going bad and causing the anomaly due to a voltage drop that goes low enough to cause the RTU to shut off but stay high enough to keep the controller happy. Obviously if the RTU drops out the siren will keep running in whatever signal it got stuck in until it satisfies the tone duration of 3 minutes or the batteries actually get low enough to make the controller drop out from the low voltage. This becomes a big problem in the long run, because eventually the batteries will get to the point where the RTU will drop out at the beginning of the test, effectively making the siren "voice only." It makes it very hard to catch them when they get to that point through ambiance recordings unless it runs on a 560 Hz controller and normally stands out, and at that point they ware pretty much rendered useless when a tornado warning is issued unless you happen to be outside and catch the siren making the announcement. Since the siren controller itself never reaches the low voltage threshold the SI testing fails to catch it, and since the county does SI testing two days after the test occurs it probably gives the batteries enough time to gain some capacity for satisfy the test since it isn't actually producing tone or a voice. This has been the biggest issue with our system up to this point. Other than that and the somewhat wacky timing of the encoder when it broadcasts commands the sirens actually activate reliably for test and warnings and, as far as I can see, function just fine.


With my classes starting back this week I decided to take a trip to Atlanta to record something not a Whelen WPS-2800 series siren for once. Upon talking with Brendan I found out that there was an Eclipse 8 installed in north Fulton County west of Roswell in the very small city of Mountain Park, GA. I few months ago I took a trip to Nashville and got to see one of their Eclipses, and I've been dying to hear one since then. I figured it was probably the most unusual siren in the area given most of the systems in ATL are pack with Vortexes, 2800's, 2001's, and a few extra bit sprinkled in the mix with some systems like Dobbins AFB, KSU, and Decatur and Duluth (E-Classes, I-Forces and an E-Class, T-121's respectively) and a few others with Mods, Sentrys, and Loudouns. The 8 stood out since it's the only one in the area and one of three that have been found in the state up to this point. My plan was to record this siren at noon and record the T-121 in Decatur that replaced the Vortex I recorded two years ago. I wanted to see how both did head to head since they are mostly the siren siren with slight differences and how they compared to a 7V8-B since it and the T-121 are rated at 121 dB. Brendan and I get to the Eclipse, noon passes, nothing. Off in the distance we hear 2001's from the Cherokee County system ramp up and a Vortex from Cobb County's system that replaced a 2001-SRN a couple years ago start a few seconds later. I called the city about the situation and got a very interesting response. Apparently they heard the surrounding sirens go off but never noticed that their siren failed. The way the lady put it on the phone was that it failed to go off with the "rest of them." That kind of throws the ownership of this siren and what network it operates on up in the air. Is it one Cherokee's system or Milton's system, I have no idea. Like the system in Columbus, the system in Cobb is equipped with Motorola ACE3600's, which this siren didn't have or at least not in a separate box. Either way, this siren failed to go.

Later on that day I followed through with my plan to record in Decatur. I get there and set my camera up. 5PM passes, no sirens. A minute later the T-121's lit up the air with this one not making a peep. While this was a disappointment, it wasn't a complete waste of time. In my recording of the Vortex I could clearly hear the 2900 installed at Agnes Scott College about 0.4 miles away. I knew I wouldn't be able to hear it going off in the distance due to the omnidirectional nature of the T-121 drowning it out. I originally planned on placing my old iPhone 4 that I re-purposed as a dedicated audio recorder near the campus, only to find out that I forgot to bring it. Turns out it wouldn't have made a difference. Now that the system has been replaced the siren no longer is tied into the city's network. I was half expecting it to be retrofitted with a CompuLert RTU, have it's controller replaced, or outright replaced with an I-Force 1600. I didn't hear it in the ambiance, nor did I hear anything that sounded like an ASC electronic controller. At this point it doesn't seem like they test their Whelen with the city system, at least audibility anyway. Something that I can say is that the T-121 is an impressive siren. I'm not a fan of the pitch they run on the rectifier (I've always favored them more peaking under 500 Hz), but they are pretty effective and carry very well for being almost a mile away in some cases.

Proud owner of a Model 1.
DJ2226's YouTube Page

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