OP25

Pi 3 Setup

Install current version (9) of debian flavor linux

Pre-built image with SDR tools, does not have OP25 installed: https://pisdr.luigifreitas.me

P25 (EBRCS)

Get the code and run the install script to build and install: https://github.com/AaronSwartzDay-SSP/op25

Configure trunk.tsv to set proper talk group (0x1f1) and mode

rx.py --args 'rtl' -N 'LNA:47' -S 2500000 -x 2 -f 772.8437e6 -o 17e3 -T trunk.tsv -V -2 -U 2> stderr.2

Note: this tends to come in garbled, you also have to be in range of the actual signal, there are several sources around the bay area, this is specifically for the Southwest Region, which covers a large radius from around Union City. Nudging the frequency '<' or '>' from the terminal seems to help lock in a clear demodulation.

Resources

• https://www.hagensieker.com/wordpress/2018/07/17/op25-for-dummies/
• https://www.sigidwiki.com/wiki/Project_25_(P25)
• https://drive.google.com/file/d/1siOQ2AIjDnvdMPWu7WqDhQKSByg7HIRJ/view
• https://hackaday.com/2019/12/20/all-your-sdr-software-in-a-handy-raspberry-pi-image/
• https://github.com/AaronSwartzDay-SSP/op25/blob/master/README-rpi3-liquidsoap