Basic setup of RTL-SDR shenanigans on Linux. The following instructions will set up the most basic and requisite drivers to let you do some cool SDR stuff on your Linux box. The instructions start for local command line operations directly on the machine and also for setting up rtl_tcp or SoapySDR remote receiver units.
CAVEAT #1: Go Wired for remote receiver units
If you are building a remote receiver -- say, something to put outside or up in your attic -- and thinking about using either rtl_tcp or SoapySDR to control them, then your experience will be immeasurably better with wired connections... in my experience. Maybe you have a super high speed greased angry pixie network operating over a perfect vacuum in your home and wifi will be fine. But probably not.
Script that does all of the following is OVER HERE, now with prompts! This allows you to run the script to re/install components without overwriting things you want to keep untouched.
CAVEAT: Two SDR drivers enter...
So, the OsmoCom RTL-SDR drivers are great and work for most things SDR. Indeed, most users seem to prefer you install these. HOWEVER, if you're on a Debian system, you can also install pre-compiled drivers with sudo apt-get install librtlsdr0 librtlsdr-dev. And the Soapy install script seem to do this anyway. So this may render your OsmoCom drivers broken and you'll get some crashes/errors complaining about undefined symbol or some nonsense.
Editorial opinion: I wish the world would just settle one method and stick to it. But I get why it doesn't. So this is something to watch out for.
Explanations of those prompts as well as detailed steps and instructions follow.
I say maybe because if you are only interested in Soapy, you might be able to skip this. Oddly enough, several pages I found with instructions for installing SoapySDR seemed to want you to install these first... for Reasons?? In any case, installing these first, and letting the script install the udev rules, only to be overwritten by SoapySDR will not hurt.
Excellent instructions at satsignal.eu. Distilled down here:
sudo apt-get update
sudo apt-get upgrade
sudo printf 'blacklist dvb_usb_rtl28xxu\nblacklist rtl2832\nblacklist rtl2830' > /etc/modprobe.d/nortl.conf
sudo apt-get install git-core
sudo apt-get install git
sudo apt-get install cmake
sudo apt-get install libusb-1.0-0-dev
sudo apt-get install build-essential
git clone git://git.osmocom.org/rtl-sdr.git
cd rtl-sdr
mkdir build
cd build
cmake ../ -DINSTALL_UDEV_RULES=ON
make
sudo make install
sudo ldconfig
cd ~
sudo cp ./rtl-sdr/rtl-sdr.rules /etc/udev/rules.d/
git clone git://github.com/MalcolmRobb/dump1090.git
cd dump1090
make
sudo reboot
pip install pysrtlsdr
git clone https://github.com/adafruit/FreqShow.git
See installation and usage instructions in the guide at: https://learn.adafruit.com/freq-show-raspberry-pi-rtl-sdr-scanner/overview
git clone https://github.com/pothosware/SoapySDR.git
cd SoapySDR/
mkdir build
cd build
cmake ..
make
sudo make install
sudo ldconfig
git clone https://github.com/pothosware/SoapyRTLSDR.git
cd SoapyRTLSDR/
mkdir build
cd build/
cmake ..
make
sudo make install
SoapySDRUtil --probe="driver=rtlsdr"
git clone http://github.com/pothosware/SoapyRemote.git
cd SoapyRemote/
mkdir build
cd build/
cmake ..
make
sudo make install
git clone https://git.osmocom.org/op25
cd op25
./install.sh
The OsmoCom drivers come with some really cool utilities for listening to various modes. Check out more info right over here. Included is the rtl_tcp remote receiver utility, which I have used with GQRX on Mac. The OsmoCom drivers are usually sufficient, and necessary, for running other SDR utilities. There is a set of Debian drivers that you can fetch using apt-get that seem to work just as well. These seem to be the two competing drivers. Sometimes if an app is expecting one and you have the other installed, it might fail with an error message, so be careful of that.
To run the Soapy business, just type:
You'll get some output like the following. The SDR remote will be ready to shoot data into your local machine. I use a Mac and CubicSDR, though I suggest probably running a fast Linux machine or, I guess, a Windows machine, if you must, as those platforms have more apps than the Mac. And as you operate things on your actual machine, the open terminal on the SDR will spit out some status messages.
Once you are satisfied that it all works, you should probably set up the remote receiver machine to do this automatically on boot up. Then you can put this up in an attic or your yard or sneak it onto a rooftop somewhere.
I have just recently started messing with P25, primarily because I wanted to follow police traffic in the aftermath of protests supporting Black Lives Matter in May/June 2020, when I noticed traffic switched from regular trunked traffic to P25 encoded channels. Also, I do not have the monies to shell out for commercially available P25 Phase 2 scanner.
It seems that the first trick is to find the Control Channel. The second trick is to futz with some command line switches to receive meaningful signals. I have not yet gotten it to work, tho progress is occuring. So here are some resources: