Since I posted my original articles on configuring the Gnuradio-based op25 P25 trunking scanner, there’s been a lot of progress in the code. In particular, there is a new fork that changes the program to a command-line version, which saves a lot of CPU resources and also offers added features. The new version will run nicely on a Raspberry Pi 3, and probably on an RPi 2 as well. Following are instructions to install it from scratch on the PI.
Download the “raspian-stretch” image from raspberrypi.org and copy the image to an 8GB SD card. There’s a very nice free tool to do that called Etcher. Install the card in your Raspberry Pi, and connect the Pi to the internet.
Open a terminal window to run all the following steps.
First, update the system and add the “sources” repository:
sudo nano /etc/apt/sources.listand remove the “#” from the beginning of the line that includes “deb-src”.
sudo apt-get update
sudo apt-get dist-upgrade
git clone https://github.com/boatbod/op25.git
- The program and config files are buried several layers down in the op25 directory. I make a symbolic link called “scanner” to that directory:
ln -s /home/pi/op25/op25/gr-op25_repeater/apps /home/pi/scanner
- The program command line requires a whole bunch of parameters that are hard to type (and to remember!). I create a shell script to start the program:
/home/pi/scanner/rx.py --args 'rtl' --gains 'lna:35' -S 250000 -f 853.6e6 \
-g 100 -q -1 -o 50000 -T /home/pi/scanner/trunk.tsv --udp-player -v 5 2>stderr.2
Reboot the system before the next step.
Now, download and build the op25 code:
It will take a while to download and install all the packages, and then compile the op25 code. But when the installation finishes, you should be all set to go. But there are a couple of additional things that I do on my system to make life a little easier: