gr-VWS-Project

This repository is to provide GNU Radio support for the Vienna Wireless Society SDR Project. See the description at Vienna Wireless Society Software Defined Receiver.

My development plan:

• Simulate the VWS SDR functionality with GNU Radio using a FunCube Pro Plus.
  • FunCube to audio or ZMQ on Lenovo
  • FunCube to audio or ZMQ on rPi
• Build a GNU Radio flowgraph for a SSB receiver using the simulation above.
  • SSB_rcv for ZMQ on Lenovo
  • SSB_rcv for audio on Lenovo

Prerequisites

• What is GNU Radio?
• Installing GNU Radio

Installation

IMPORTANT NOTES:

• These instructions are written for a Linux OS. Similar commands work for Mac and Windows.
• Use the clone command rather than downloading a Zip file!

1. Open a terminal window.
2. Change to the home directory.

cd ~/  

3. If you don't have 'git', enter

sudo apt install git  

4. Clone the repository:

git clone https://github.com/duggabe/gr-VWS-Project.git

For the original project only

1. To use the FunCubePro Plus dongle, you must install gr-funcube using a terminal screen as follows (one line at a time):

cd $HOME
sudo apt install libusb-1.0-0-dev libudev-dev libhidapi-dev
gnuradio-config-info --prefix
git clone https://github.com/dl1ksv/gr-funcube.git
cd $HOME/gr-funcube
mkdir build
cd build
cmake -DCMAKE_INSTALL_PREFIX=<prefix from gnuradio-config-info> ../
make
sudo make install
sudo ldconfig
cd /etc/udev/rules.d
sudo cp $HOME/gr-funcube/50-funcube.rules ./
sudo udevadm control --reload-rules
sudo udevadm trigger

Once gr-funcube is built, gnuradio needs to find it so you don't get an error about "failure to import funcube". So, do the following steps.

2. In a terminal screen enter

find {your-prefix} -name gnuradio | grep "packages"  
find {your-prefix} -name funcube | grep "packages"  

3. Continue by following ModuleNotFoundError#C._Setting_PYTHONPATH

For Ubuntu 24.04.1 and GNU Radio v3.10.9.2 I added this to my .bash_aliases file:

export PYTHONPATH=/usr/lib/python3/dist-packages:/usr/lib/python3.12/site-packages:$PYTHONPATH
export LD_LIBRARY_PATH=/usr/lib:$LD_LIBRARY_PATH

4. On your terminal enter exit. Then start a new terminal.

Summary of flowgraphs

Original SDR Project

VWS_SDR_sim_1 - original testing with GUI, audio or ZMQ out
VWS_SDR_sim_2 - model of VWS SDR - no GUI, remote frequency set, audio out
VWS_SDR_sim_3 - model of VWS SDR - no GUI, remote frequency and gain set, ZMQ out
VWS_SDR_sim_4 - model of VWS SDR - no GUI, remote frequency and gain set, audio out

SSB_rcv_1 - original testing with GUI, ZMQ in
SSB_rcv_2 - original testing with GUI, audio in
SSB_rcv_3 - full GNU Radio SSB receiver with GUI, ZMQ in, Weaver method
SSB_rcv_4 - full GNU Radio SSB receiver with GUI, audio in, Weaver method
SSB_rcv_5 - full GNU Radio SSB receiver with GUI, ZMQ in, filter method
SSB_rcv_6 - full GNU Radio SSB receiver with GUI, audio in, filter method

Presentation on October 10, 2025

RTL_SDR_rcv.grc             Completed flowgraph from tutorial
RTL_SDR_p1.grc              RF front end for SSB receiver
RTL_SDR_p2.grc              Baseband tuner for SSB receiver
RTL_SDR_p3.grc              Completed SSB receiver
SSB_demo.grc                SSB simulation; showing sidebands
VWS_GR_presentation.txt     Outline, links, and summary of files
VWS_SSB_presentation.odp    Presentation slides

Operation

Original SDR Project

NOTES:
The package uses two separate processes: (a) the VWS_SDR Simulation and (b) a SSB Receiver. These run in two separate terminal windows (or tabs).

VWS_SDR Simulation

1. Open a terminal window on the computer where the VWS_SDR Simulation will be executed.
2. Go to the gr-VWS-Project folder.

cd ~/gr-VWS-Project

3. Execute gnuradio-companion.

gnuradio-companion

4. Open the VWS_SDR_sim_4.grc flowgraph.
5. If VWS_SDR_sim_4 is not to run on the same computer as the SSB receiver, change the ZMQ SUB Message Source address to the IP address of the computer running the SSB Receiver; for example: tcp://192.168.1.194:49204
6. Click 'Generate the flowgraph' or press F5.
7. Exit gnuradio-companion by clicking the "X" in the upper right corner of the screen.
8. On the same terminal screen, execute the VWS_SDR Simulation

python3 -u VWS_SDR_sim_4.py

9. There is no GUI, but informational messages will be given during the program startup and operation. To terminate the program, press the "Enter" key.
10. Note: For subsequent executions of the program, if there are no changes to the flowgraph, you can skip steps 3 through 7.

SSB Receiver

1. Open a second terminal window on the computer where the SSB Receiver will be executed.
2. Go to the gr-VWS-Project folder.

cd ~/gr-VWS-Project

3. Execute gnuradio-companion.

gnuradio-companion

4. Open the SSB_rcv_6.grc flowgraph.
5. If SSB_rcv_6 is not to run on the same computer as the VWS_SDR Simulation, change the ZMQ PUB Message Sink address to the IP address of the computer running the SSB Receiver; for example: tcp://192.168.1.194:49204
6. Click 'Generate the flowgraph' or press F5.
7. Exit gnuradio-companion by clicking the "X" in the upper right corner of the screen.
8. On the same terminal screen, execute the SSB_rcv_6 flowgraph.

python3 -u SSB_rcv_6.py

9. A new window will open showing various controls, a waterfall display, and a Frequency display. The receive frequency can be changed in three ways: (a) by clicking on the digits, where clicking on the uppper part of the digit increases the value, and clicking on the lower part of the digit decreases the value; (b) by double clicking on the waterfall display at the desired frequency; or (c) by entering the desired frequency in the "Quick Set Frequency" box. That value is in Hz and can be the complete integer digits (e.g. 14250000) or in scientific notation (e.g. 14.25e6).
10. To terminate that window, click the "X" in the upper right corner.
11. Note: For subsequent executions of the program, if there are no changes to the flowgraph, you can skip steps 3 through 7.

Testing

For testing with an audio cable between the VWS_SDR_sim_4 and the SSB_rcv_6 programs, audio dongles seem to work better than integrated sound cards. The audio level of the input to SSB_rcv_6 needs to be adjusted so that it is high enough to provide a good signal, but not overdriving the input.

To test with ZMQ (TCP/IP) links between the VWS_SDR_sim and the SSB_rcv programs, using VWS_SDR_sim_3 and SSB_rcv_5 has given good results. The "Screenshot from 2025-02-10.png" shows an "over the air" signal. Even though the level was not much above the noise floor, the audio was clear and easy to understand.

Presentation on October 10, 2025

1. Open a terminal window.
2. Go to the gr-VWS-Project folder.

cd ~/gr-VWS-Project

3. Execute gnuradio-companion.

gnuradio-companion

4. Open the RTL_SDR_p3.grc flowgraph.
5. Execute the flowgraph by selecting the menu items "Run -> Execute" or pressing F6.
6. To terminate the RTL_SDR_p3 window, click the "X" in the upper right corner of that window.
7. Exit gnuradio-companion by clicking the "X" in the upper right corner of the screen.