Back in 2015 we posted about the dsame software, which is a decoder for the American Emergency Alert System (EAS) which is encoded with the SAME (Specific Area Message Encoding) protocol. EAS transmits on the NOAA weather frequency.
The sirens appear to be activated wirelessly through the same frequencies that weather and EAS use, and so the signal can be monitored with an RTL-SDR or other SDR. When an active signal is present, the forked dsame software will decode the alert. The alert could then be used to activate a local siren or display.
Local EAS weather alerts are encoded with the SAME (Specific Area Message Encoding) protocol. They are transmitted on the local weather radio frequency in the USA and Canada and some weather radio’s are capable of decoding the EAS SAME data. Cuppa-joe’s dsame EAS decoder outputs full EAS weather messages such as:
The National Weather Service in Pleasant Hill, Missouri has issued a Required Weekly Test valid until 12:30 PM for the following counties in Kansas: Leavenworth, Wyandotte, Johnson, Miami, and for the following counties in Missouri: Clay, Platte, Jackson, Cass. (KEAX/NWS)
To use the software you will still need to use a EAS demodulator such as multimon-ng which is available for Windows and Linux, and you will also need Python 2.7+ installed.
An example EAS SAME alert can be heard in the player below:
This software along with a supported USB software defined radio turns your Android device to a portable weather radio.
* Listen to weather radio in the US/Canada.
* Decode EAS Alerts US/Canada
* Selectable Pre-defined Frequencies
* Alert Notifications
* Widget to display alerts
* Option to unmute audio when alert recieved
* FIPS and CLC Location Code Databases
* Event Code Database
* No internet connection required
Possible future features
* Switch to using rtl_tcp_andro
* Option to only show alerts if you are currently in the affected region
* Affected region map
The EAS is a national public warning system that requires broadcasters, cable television systems, wireless cable systems, satellite digital audio radio service (SDARS) providers, and direct broadcast satellite (DBS) providers to provide the communications capability to the President to address the American public during a national emergency. The system also may be used by state and local authorities to deliver important emergency information, such as AMBER alerts and weather information targeted to specific areas.
Reddit user rtlsdr_is_fun is working on software to automatically detect an EAS broadcast from a NOAA Weather Radio stream using an rtl-sdr (or any SDR, or even an internet stream) and then immediately play it and record it. This will allow the EAS alert to be heard up to 2 minutes faster than email/sms alerts, without the need to constantly listen to the NOAA WX Radio.
He stresses that his software is still in the very early alpha stages, but you can read about his project on his Reddit post here, which also contains a download link.