About the Warren County Communications Archive
This service is brought to you by the merry bunch of jackasses of the 721st Mechanized Contest Battalion!This system uses "Software Defined Radio" to monitor several channels simultaneously. In the classic sense there are no radios or scanners used to capture audio. The system currently runs on a surplus four core Intel ATOM system with two RTL-SDR sticks to provide the radio frequency interface.
The core technology is an application called "GNU Radio" a development toolkit that provides signal processing blocks to implement software radios. What was previously done with discreet electronic components can now be done with a few lines of C++ or Python code.
The main program, built from GNU Radio, is called "multirx" (short for multi receiver). With the current hardware, it can listen to a 1.8 MHz segment of radio spectrum and simultaneously receive multiple channels. This is different from a scanner which switches between many channels but can only receive one at a time. Each channel is recorded digitally as well as streamed live. The recordings are stored as timestamped audio files with dead-air removed.
A second program "wave2ttd", a two-tone decoder, listens to the Warren County Alerts Paging Channel (fed from multirx), decodes the two-tone sequence, and saves the page audio categorized by the unit requested. Optionally, it could be configured to send an email, text, or phone call to subscribers that wish to be notified.
Both programs are provided as Free and Open Source and can be found on GITHUB.
The channels currently monitored and recorded are:
SDR#1
Warren County Fire Response 155.76 MHz
Police Central (Belvidere, Oxford, Washington Boro/Twp) 155.82 MHz
SDR#2
Warren County EMS Responce 158.745 MHz
Warren County Alerts (Paging) 159.18 MHz
(Other channels could be added at a later time.)
Comments, questions, concerns?? Send a note off to nnj at ka2pbt.com