Twin Cities siren activation frequency

[STHboy]

Well it's that time of the year again. I'll be going to St. Paul, MN and should be there to catch the August siren test. Similarly to last year, I'll be armed with an iRiver H340 MP3 player/recorder plus a few external mics and will be attempting a second recording - probably on a specific dual-tone Allertor this year rather than the mix of sirens that I recorded last year.

An idea I had was to do a recording which not only gets the sirens, but also captures the audio on the activation frequency. Brent did such a recording a few years back, see the bottom of this page. Therefore, does anyone know the activation frequency for the Minneapolis/St. Paul siren system? This would the the frequency you'd set your scanner to, not the frequency of the activation tones. Judging by the look of the antennas attatched to the siren controllers, I'd guess it's in the 150MHz business band, but that's a huge band! "Weapons" of mine include a Yaese VX-7, a VX-2, and an Alinco DJ-196T, so I'm pretty frequency agile.

So do we have any Twin Cities scanner buffs who know that frequency?

[STHboy]

The siren test is tomorrow, and I have yet to get a response. So I'll throw it up again and see if I get a last minute response.

I'll be recording the Allertor from Central Park in the St. Anthony district of St. Paul, and will be located across the park so it's not horribly loud. I'm also going to leave a recorder rolling at my cousins' house and see what it picks up.

Or maybe we'll have bad weather and no test at all. Guess we'll find out!

[quiksmith10]

I don't know St. Paul's frequency but my best bet would be to do a google search on St. Paul frequencies. If this doesn't work, try RadioReference at the link I provided below. It's a list of St. Paul frequencies. Although I don't see a frequency listed specifically for the sirens, they might use one of the other frequencies listed there. Are the sirens controlled by the City of St. Paul or by Ramsey County?

http://www.radioreference.com/modules.p ... &ctid=1371

[STHboy]

Thanks for the reply there. I've spent many hours googling over that frequency with no clear result! One site I ran across said all of the Twin Cities sirens were activated by the Hennepin County Sheriff. Then I ran across a frequency marked "Civil Defense" under Hennepin County on RadioReference. So I brought the VX-2 and tuned it to that frequency - 155.055 MHz. I did hear a series of packets a few seconds before the Allertor started, but not before the second round of sirens went off. So who knows. Oh well, it's in the recording, and it adds some spice to it!

The St. Paul siren test went well. I had recorders in two different locations for the test - one with me in front of the Allertor at Central Park in St. Anthony (iRiver H340 with Sony ECM-DS70P mic) and another one in the Highland district of St. Paul at my cousins' house (Dell Inspiron 4000 laptop, using Cool Edit Pro 2.0 and an Audio-Technika MB2000L mic.) Both recorders picked up good audio - the iRiver got the Allertor with minimal distortion, and the laptop picked up a whole slew of sirens - the informal count so far includes two T-1000s, one T-1000T, at least two 2001s, and some 8-port directional siren - possibly a T-128, although I have yet to see one in this area.

So I figure I'll ask the ham operators around here if they know that frequency for next year's recording - they'd be the ones who'd know. As far as sharing these recordings, I'll find a way to do that after I've normalized the recordings in Cool Edit. In any case I'll definately send those - and the one from last year - to the Siren Archive.

[Midwest Siren]

So if you can figure out what the frequency is is there a possible way to manipulate that frequency? Im just asking I don't plan on doing anything.

[Elliott]

So if you can figure out what the frequency is is there a possible way to manipulate that frequency? Im just asking I don't plan on doing anything.

Most likely not. The data packets heard are probably FSK (Frequency Shift Keying), which requires specialized equipment to interact with. It is an actual security measure, to prevent "manipulation". This is an improvement over DTMF (keypad tones), which was capable of "manipulation".

[Midwest Siren]

So basically today it is impossible to manipulate a signal used to activate sirens in order to activate it.

[Elliott]

I'd say difficult, at least for the average person. I'm not even gonna give suggestions of how to, which could contribute to mischief in one's mind. I'll just say its not easy to by any means.

[Midwest Siren]

I'm pretty sure you would get in federal trouble especially if you sounded one in attack. Because in Omaha we only use the Alert signal so anyone who remembers the cold war and Duck and Cover will go beserk if they hear the Attack signal.

[birdy]

Back in 1997 I believe, some dorkass figured out how to set off our thunderbolts using a ham radio, which in turn contributed to their demise. And kept me up all night.

Bastard.