Most I of those we installed ages ago are VHF but the only trigger is either a 2 tone or 5/6 tone paging format. Anyone can duplicate them with a $250 old service monitor off eBay or with a sound card and some specs. Feed that audio into a transmitter and it is pretty simple.
All the old service monitors had all the common formats used in rf. On Sun, Apr 9, 2017, 10:28 AM Chuck McCown <[email protected]> wrote: > I forgot to mention, our whole system was paid for by the feds about 20 > years ago due to the nerve gas incinerator. > > *From:* Chuck McCown > *Sent:* Sunday, April 09, 2017 9:24 AM > *To:* [email protected] > *Subject:* Re: [AFMUG] Were you bored this weekend Chuck ? :) > Where I live this half of the county is totally covered. Each Wednesday > at 3pm it says : “this is a test, this is a test, this is a test of the > Tooele county emergency warning system”. Looks like 900 MHz feeding the > system. Many times I have thought about commandeering the system to > announce the return of Jesus or something. > > *From:* Colin Stanners > *Sent:* Sunday, April 09, 2017 3:52 AM > *To:* [email protected] > *Subject:* Re: [AFMUG] Were you bored this weekend Chuck ? :) > > If it's an old system, it's very possible there's nothing desirable like > authentication/encryption - it may just be "turn on the sirens if you see > any signal on the frequency of 155.555mhz" Anyone with some RF knowledge, a > $300 SDR (HackRF One) and a $50 amateur radio flea market "2 meter band" > amplifier could blanket a city with such a signal. > > On Sun, Apr 9, 2017 at 1:15 AM, CBB - Jay Fuller < > [email protected]> wrote: > > > Sirens are bad right ? > > Create a custom radio on a certain frequency? I am sure these things are > set off with a radio right.... > > > https://www.usatoday.com/story/news/2017/04/08/hacker-triggers-all-156-emergency-sirens-dallas/100212412/ > > > Sent from my Verizon 4G LTE Smartphone > > >
