New Watch Duty Scanners

December 12, 2022

Did you know that Watch Duty reporters monitor first responder radio communications in real-time 24/7?  This is how we are able to relay information to you so fast – but if we can’t hear, we can’t help.

After identifying millions of acres of Internet radio dead zones throughout the state we knew that in order to serve our community better we had to take a hard swing at solving this problem.

Our volunteer team has gone above and beyond the call of duty again to build radio scanners that are being deployed throughout California to these dead zones to ensure that our reporters can hear into the deepest forests.

Our Watch Duty Scanners are capable of capturing first responder radio communications as well as aircraft transponders and relay them over the Internet making these communications available to Watch Duty Reporters and the public at large. Interested in the tech?– see the technical details at the bottom of this email.

Our plan for 2023 is to complete our deployment of our scanners throughout all of California so there are no more dead zones and we are able to confidently monitor the entire state – rural or not.  But to do this, we need your help.  Your donations will help us to deploy scanners everywhere to help keep you safe.

Technical Details

Each Watch Duty Scanner is made up of the following components:

  • Wide band receive antenna
  • Multiple Software Defined Radios (SDRs)
  • Raspberry Pi Single Board Computer (SBC) running Linux
  • Open Source Software for signal processing and Radio Frequency (RF) demodulation
  • Custom software for tone detection and alerting - reporters receive alerts at the same time the fire station
  • Remote administration and monitoring

Each Watch Duty Scanner uses a modular architecture that can scale as needed to each deployment location.  Our largest scanner to date uses 8 SDRs to capture 16 MHz of RF bandwidth and is processing 75 simultaneous audio channels, merging them into 8 stereo streams organized by agency, while at the same time tracking aircraft positions with ADS-B.  We are currently targeting the following RF bands:

  • VHF Airband (108-137 MHz)
  • Public Safety VHF High band (150-174 MHz)
  • ADS-B (1090 MHz)

Audio feeds from our Watch Duty Scanners are being shared with the public using and the aircraft positions are shared using ADSBExchange which feeds Flight Tracker 24 among others. Here is our Siskiyou County Fire feed where the deadly Mill Fire took place earlier this year.