Smaller radio systems can be covered using a Raspberry Pi. If you are interested in doing this, you should really get a Pi 4. It maybe possible to get things running on an older Pi, but you often get unexpect behavior and errors. A Pi 4 can handle 3-4 simulatanious recordings. Make sure you have a good power supply. Also pay attention to heat. If the Pi gets too hot, it will slow down. A good case or fan can help keep it going full tilt. You can also just run debian on a NUC or Miniform PC. These commands will work with a vaneilla debian install as well.
This is a good guide on how to setup a Raspberry Pi in headless mode. This means that you do not have to attach a monitor, keyboard or mouse to it to get it working. The steps below are pulled from this guide.
The first step is to put the Raspberry Pi OS onto a MicroSD card. You will need to have a USB MicroSD card adaptor, so you can connect it to your computer. Either of these approaches should work:
- Download the Raspberry Pi OS Lite image.
- Install Raspberry Pi OS using Raspberry Pi Imager which can download and burn the image above.
After the OS has been written to MicroSD card, we need to change a few files so that the Pi can get on Wifi and also allow for SSH connections. See the guide for how to do it using Windows.
- On a Mac
touch /Volumes/boot/ssh
- Next, add the WiFi info
nano /Volumes/boot/wpa_supplicant.conf
country=US
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
network={
ssid="NETWORK-NAME"
psk="NETWORK-PASSWORD"
}
- Eject the MicroSD card (first in the OS and then physhically from the reader)
- Put the MicroSD card in the Pi and power it on.
This is a good guide for how to find and connect to a Pi on your network.
These steps should work on a Mac and assume you only have one Pi on the Network
- Check to see if it is up:
ping raspberrypi.local
- Clear old known hosts:
ssh-keygen -R raspberrypi.local
- See if you can connect:
ssh [email protected]
*default password is: raspberry * - Exit:
exit
- Create your SSH keys if you don't have them yet:
ssh-keygen
- Send over you keys:
ssh-copy-id [email protected]
The following steps setup all of the libraries needed to build Trunk Recorder.
- Add the Debian Multimedia source and include non-free libraries, like fdkaac. Edit the sources.list file:
sudo nano /etc/apt/sources.list
- and add this line to the end:
deb http://www.deb-multimedia.org/ bullseye main non-free
- Download the keys for the apt source and install them:
wget https://www.deb-multimedia.org/pool/main/d/deb-multimedia-keyring/deb-multimedia-keyring_2016.8.1_all.deb
sudo dpkg -i deb-multimedia-keyring_2016.8.1_all.deb
- Update the OS:
sudo apt update
sudo apt upgrade
- Add all of the libraries needed:
sudo apt -y install libssl-dev openssl curl git fdkaac sox libcurl3-gnutls libcurl4 libcurl4-openssl-dev gnuradio gnuradio-dev gr-osmosdr libhackrf-dev libuhd-dev cmake make build-essential libboost-all-dev libusb-1.0-0-dev libsndfile1-dev
Configure RTL-SDRs to load correctly:
sudo wget https://raw.githubusercontent.com/osmocom/rtl-sdr/master/rtl-sdr.rules ~/rtl-sdr.rules
sudo mv ~/rtl-sdr.rules /etc/udev/rules.d/20.rtlsdr.rules
You will need to restart for the rules to take effect. Logging out and logging back in will not be enough.
sudo shutdown -r now
Now go Build Trunk Recorder!
Ubuntu has a very good guide on setting up Ubuntu Server to run on a Raspberry Pi. Follow this to get started.
sudo apt update
sudo apt upgrade
sudo apt install -y apt-transport-https build-essential ca-certificates fdkaac git gnupg gnuradio gnuradio-dev gr-osmosdr libboost-all-dev libcurl4-openssl-dev libgmp-dev libhackrf-dev liborc-0.4-dev libpthread-stubs0-dev libssl-dev libuhd-dev libusb-dev pkg-config software-properties-common cmake sox libsndfile1-dev
If you are using a HackRF:
sudo apt install -y hackrf libhackrf-dev libhackrf0
Configure RTL-SDRs to load correctly:
sudo wget https://raw.githubusercontent.com/osmocom/rtl-sdr/master/rtl-sdr.rules /etc/udev/rules.d/20.rtlsdr.rules
In order to keep your copy of the Trunk Recorder source code free of build artifacts created by the build process, it is suggested to create a separate "out-of-tree" build directory. We will use trunk-build
as our build directory.
Assuming you are in the desired directory to place both trunk-recorder and trunk-build folders to, perform the following...
cd ~
mkdir trunk-build
git clone https://github.com/robotastic/trunk-recorder.git
cd trunk-build
cmake ../trunk-recorder
make -j `nproc`
sudo make install
Note: If the Pi hangs during the make -j 'nproc'
command, try make
instead (it may take longer but may also prevent locking up the Pi due to all processor cores being 100% in use)
(It takes about 15 minutes for this section.)
Run the command volk_profile
to ensure that VOLK (Vector-Optimized Library of Kernels) uses the best SIMD (Single instruction, multiple data) architecture for your processor.
The next step is to configure Trunk Recorder for the system you are trying to capture.
If all goes well you should now have the executable named trunk-recorder
, and created the config.json
configuration file as described in the Wiki and README.
From your build directory (e.g. trunk-build
) you can now run
./trunk-recorder
Trunk Recorder will look for a config.json file in the same directory as it is being run in. You can point it to a different config file by using the --config argument on the command line, for example: ./trunk-recorder --config=examples/config-wmata-rtl.json
.