Need Help Finding Activation Frequency

[MisterTwister55]

This Thursday, the TMI sirens will be tested. For the past year, I've been looking for the frequency of activation to monitor with my scanner to get an advanced warning for when they start the test. They do a radio test every Thursday morning and a growl the first Thursday of the month. They only do one annual test, so I want to make the most out of it. I did various searches for FCC licenses, but I don't know what I'm looking for. I'm not sure if the licensee is Dauphin County Emergency Management or K&C Communications. KC does the Thursday tests but the county does the yearly test.

Hopefully you can understand why I don't want to call County or the Communications because they would think I want the frequency for malicious purposes. I don't. I've seen enough sirens go off in my life. I'm a licensed operator and I know the consequences for transmitting out of band and activating sirens. That's an arrestable offense. I know you guys understand.

I don't necessarily even need the exact frequency, maybe just the band. Heck my scanner is so good that it has a signal stalker and other search modes that I can find it if I can pin point the band.

Any help will be appreciated, even if that's just discussing the probability of different licensees.

[Archon]

Go here and get a account It is free and someone on the forum will know the freq

http://www.radioreference.com/

[MisterTwister55]

I've been using radio reference for a few years now and especially last year for the frequency. Nothing.

[Rheems1]

Scan the 450mhz band...I don't know what the exact frequency is but the activation takes place on the 450mhz band. You will hear a couple of tones, the first is the activation tones (DTMF)... the second one is awful sounding SCADA tones as it polls all of the sirens... now here is where it gets goofy... next you will hear the sound of information packets being sent... this is Lancaster County setting off THIER section of sirens (Each County has to do it's own activation)... finally you will hear what sounds like 2+2 Motorola Quik-Call 1 tones (they aren't.. they are the ugly paging tones used over hospital systems) and that is York County setting off thier system...all three frequencies are seperated by .25 mhz (in this example we will say that Dauphin Operates on 451.825, Lancaster would operate on 451.850 and York County would be on 451.875.. those are not the right frequencies mind you) and are done in such a way that all the systems piggyback (so the Dauphin tones sound, 5 seconds or so later the Lancaster tones go out and than the York tones go) so you can catch all of them if you are quick. Here is the stupid thing, there ARE a couple of TMI sirens in Cumberland County... I HAVE no idea how they are set off. Also, for in case anyone is wondering there is only 1 decoder in the boxes.... when TMI hits thier button it sends out data squirt to each of the county's terminals which automatically activates them in the proper mode. I can't speak for why it is set up like this other than to tell you that each county maintains thier own controls (in Lancaster we had a Federal Commander system using data packets and we could set off sirens one at a time as well as do all of the functions such as rotation testing, motor bumps and stuff like that). Good luck with it man!!

Dave Fritz

[500AT]

The sirens at TMI, are activated on a frequency that belongs to Exelon. The County EOC, does have access to this frequency to activate the sirens. I believe, if my memory serves me correctly, it is in the 450-455 MHz area. When I was in their EOC, the FCC callsign at the bottom of the channel module for siren activation was KQH735.

[MisterTwister55]

Deleted

[MisterTwister55]

Ron,

That helps a lot. I narrowed it down to a few frequencies. I'll have to keep studying licenses to see if any of them make sense.

Thanks.

[MisterTwister55]

I'm looking at the frequencies issued for KQH735 and I think I've come up with a conclusion. All the 15 watt frequencies are the sirens. The 100 watt frequencies are the activation radios. There are 8 100 watt stations.

Does that conclusion make sense to you guys? If it does, I guess I'll have to listen to those frequencies.

[500AT]

Mike,

Some of these frequencies might be used for day-to-day operations at TMI. If you program these into your radio receiver and hear a quick key-up of the transmitter on one or more channels every 2-10 seconds, then there is a good possibility this radio system might have morphed into an LTR trunking system. With that said, the 15 watt radios could be for most anything, but is most likely for mobile radios. However, the sirens would be covered under that section of the license.

This means that anyone of the following frequencies could be used to trigger the sirens:

• * 451.0500
  * 451.1250
  * 451.2250
  * 451.3000
  * 451.3750
  * 451.5250
  * 451.6750
  * 452.1250

Given the fact they have an emission mode of 11K3F1D, this means they might be using digital telemetry to activate the sirens, rather than two-tone sequential paging that most other jurisdictions around the nation use. This newer digital method is becoming quite popular in many urban areas.

[MisterTwister55]

That is pretty much what I gathered after an hour of research. I also converted the emission types. They are 11.3 KHz FM Data...11.3 KHz FM Voice...20 KHz FM Voice.