24 September 2026

SDR Learning Module — Lesson 0

Preparing the SDR development environment with WSL2, Ubuntu, and GNU Radio.

SDR
Lesson

SDR Learning Module — Lesson 0

Preparing the SDR Development Environment with WSL2 + Ubuntu + GNU Radio

Course: Software Defined Radio (SDR)
Lesson: 0 — Environment Preparation
Target platform: Windows 11 + WSL2 + Ubuntu 24.04 LTS
GNU Radio: Install from Ubuntu binary packages
Audience: Beginner-to-intermediate engineer/researcher
Goal: Build a clean GNU Radio environment before studying DSP and real SDR hardware.

1. Learning Objectives

After completing Lesson 0, you should be able to:

Explain what SDR is at a high level.
Explain the role of GNU Radio.
Explain why WSL2 + Ubuntu is useful for SDR development.
Install and verify WSL2.
Install and verify Ubuntu.
Install GNU Radio from Ubuntu packages.
Launch GNU Radio Companion (GRC).
Understand the boundary between software-only SDR experiments and real SDR hardware.
Know how USB SDR hardware can later be attached to WSL2.

Important: Lesson 0 does not attempt to teach DSP yet. The objective is to create a reliable laboratory environment.

2. What Is Software Defined Radio?

A traditional radio implements much of the radio chain using dedicated analog/digital hardware.

A simplified traditional receiver is:

Antenna
   ↓
RF Front-End
   ↓
Mixer / Filter
   ↓
Demodulator
   ↓
Data

An SDR moves a significant portion of the signal-processing chain into software:

Antenna
   ↓
RF Front-End
   ↓
ADC
   ↓
IQ Samples
   ↓
Software DSP
   ↓
Demodulation
   ↓
Data

The central idea is:

An SDR represents radio signals as digital samples and processes those samples using software.

This does not mean that all RF hardware disappears. An SDR still needs RF electronics, ADC/DAC hardware, clocks, interfaces, and often amplifiers/filters.

3. What Is GNU Radio?

GNU Radio is an open-source framework for building software-defined radio and digital signal-processing systems.

The primary development environment we will use is GNU Radio Companion (GRC).

GRC represents a radio/DSP system as a flowgraph:

[Signal Source]
       ↓
[Filter]
       ↓
[Demodulator]
       ↓
[Data Output]

Each block performs a processing operation.

GNU Radio works primarily with streams of digital samples and also supports message-based interfaces for packet/control processing.

The important learning principle is:

Do not memorize blocks first. Understand the signal flow first.

4. Why WSL2?

For this course, WSL2 provides a practical Linux environment without requiring a separate Linux installation.

Recommended architecture:

Windows 11
    │
    └── WSL2
          │
          └── Ubuntu 24.04 LTS
                │
                ├── GNU Radio
                ├── Python
                ├── Git
                ├── SoapySDR
                ├── HackRF tools
                └── Other SDR utilities

Advantages:

Linux command-line environment
easy package management with apt
Python development
GNU Radio development
Git and compiler tools
convenient SDR software ecosystem
reproducible development environment
no need to dual-boot Windows/Linux

5. WSL2 vs Native Windows GNU Radio

| Item | WSL2 + Ubuntu | Native Windows | |---|---|---| | Linux tools | Excellent | Limited | | apt packages | Yes | No | | GNU Radio | Excellent | Available through other distributions | | Python development | Excellent | Good | | SDR research workflow | Very good | Good | | USB SDR hardware | Requires USB/IP setup | Usually direct | | Linux OOT modules | Excellent | More setup | | Recommended for this course | Yes | Optional |

The goal is not that WSL2 is universally superior. It is that it gives us a Linux-first SDR research environment while keeping Windows as the host OS.

6. Lesson 0 Architecture

We will use two stages.

Stage A — Software-only SDR

GNU Radio
   ↓
Virtual Signal
   ↓
DSP
   ↓
Spectrum / Time Display

This stage does not require an SDR device.

Stage B — Real SDR hardware

Windows USB
     ↓
usbipd-win
     ↓
WSL2
     ↓
GNU Radio
     ↓
HackRF / RTL-SDR / USRP
     ↓
RF

We intentionally start with Stage A.

7. Step 1 — Check WSL

Open PowerShell.

Run:

wsl --status

Then:

wsl --list --verbose

Expected example:

NAME      STATE      VERSION
Ubuntu    Running    2

The important requirement is:

VERSION = 2

If WSL is not installed:

wsl --install

Restart Windows if requested.

After reboot:

wsl --status

Then:

wsl --list --verbose

8. Step 2 — Install Ubuntu

If Ubuntu is not installed, first see available distributions:

wsl --list --online

Install Ubuntu:

wsl --install -d Ubuntu

If you specifically want a distribution version exposed as Ubuntu 24.04 in your environment, use the available distribution name shown by wsl --list --online.

After installation, launch Ubuntu.

Create:

Linux username
Linux password

The Linux password is separate from the Windows password.

9. Step 3 — Verify Ubuntu

Inside Ubuntu:

lsb_release -a

Expected:

Distributor ID: Ubuntu
Description: Ubuntu 24.04 LTS
Release: 24.04

Check the kernel:

uname -a

Check Python:

python3 --version

Update the package database and installed packages:

sudo apt update
sudo apt upgrade -y

10. Step 4 — Install GNU Radio

For beginners, use the Ubuntu binary package.

GNU Radio's current Linux installation guidance recommends binary packages for most users. Ubuntu 24.04 is listed with GNU Radio 3.10.9.2 in the current GNU Radio documentation.

Install:

sudo apt install gnuradio -y

Do not compile GNU Radio from source for Lesson 0.

Source compilation is useful later when you need development/customization, but it adds unnecessary complexity to the initial learning environment.

11. Step 5 — Verify GNU Radio

Check GNU Radio Companion:

gnuradio-companion --version

Then check the Python module:

python3 -c "import gnuradio; print(gnuradio.__version__)"

You can also locate the executable:

which gnuradio-companion

Example:

/usr/bin/gnuradio-companion

12. Step 6 — Launch GNU Radio Companion

Run:

gnuradio-companion

GRC should open.

If it opens successfully, Lesson 0 has reached its primary milestone.

You should be able to see the GNU Radio Companion graphical interface and create a new flowgraph.

13. Step 7 — First Flowgraph

Do not start with a real RF signal.

Create a simple software-only test:

Signal Source
      ↓
   Throttle
      ↓
QT GUI Frequency Sink

Suggested parameters:

Sample Rate = 1 MHz
Signal Frequency = 100 kHz
Amplitude = 1

The Frequency Sink should show a spectral peak around 100 kHz.

This experiment introduces:

sample rate
signal frequency
amplitude
FFT
frequency-domain visualization
GNU Radio blocks
stream connections

We will study the mathematics in later lessons.

14. Step 8 — Understand the First Flowgraph

Signal Source

Generates a digital signal.

For a sinusoid:

[ x(t)=A\cos(2\pi f t) ]

GNU Radio represents the signal as discrete samples.

Throttle

Controls the processing rate when no hardware source/sink determines the rate.

It is mainly useful in simulation flowgraphs.

QT GUI Frequency Sink

Displays the signal spectrum using an FFT-based visualization.

Conceptually:

Time-domain samples
        ↓
       FFT
        ↓
Frequency-domain display

15. Real SDR Hardware — Later

When we introduce hardware, the flowgraph becomes:

Antenna
   ↓
SDR Receiver
   ↓
IQ Samples
   ↓
GNU Radio
   ↓
Filter
   ↓
Demodulator
   ↓
Decoder
   ↓
Data

For transmission:

Data
 ↓
Encoder
 ↓
Modulator
 ↓
Pulse Shaping
 ↓
IQ Samples
 ↓
SDR Transmitter
 ↓
RF

16. USB SDR Hardware in WSL2

WSL2 does not provide ordinary USB device access in exactly the same way as native Linux.

For compatible systems, Microsoft documents using usbipd-win to attach USB devices to WSL2.

Typical workflow:

PowerShell

usbipd list

Share the selected device:

usbipd bind --busid <BUSID>

Attach it to WSL:

usbipd attach --wsl --busid <BUSID>

Ubuntu

lsusb

The SDR should then appear as a USB device.

When finished:

usbipd detach --busid <BUSID>

Do not configure this until the software-only GNU Radio environment is working.

17. Recommended SDR Software Stack

Our eventual environment:

                 SDR APPLICATION
                       │
                 GNU Radio
                       │
             ┌─────────┴─────────┐
             │                   │
         SoapySDR              UHD
             │                   │
      ┌──────┴──────┐       USRP devices
      │             │
   HackRF       RTL-SDR

Other tools will be introduced when needed.

18. Troubleshooting

Problem A — `wsl` is not recognized

Open PowerShell as Administrator and check Windows updates.

Then:

wsl --install

Restart Windows if requested.

Problem B — Ubuntu is WSL1

Check:

wsl --list --verbose

Convert it:

wsl --set-version Ubuntu 2

Verify again:

wsl --list --verbose

Problem C — GNU Radio package not found

Run:

sudo apt update

Then:

apt search gnuradio

Try:

sudo apt install gnuradio

Avoid immediately switching to a source build.

Problem D — `gnuradio-companion` cannot start

Check:

gnuradio-companion --version

Then:

python3 -c "import gnuradio; print(gnuradio.__version__)"

If Python imports correctly but the GUI does not start, capture the terminal error. The error message is more useful than reinstalling everything.

Problem E — GUI problems under WSL

WSL2 supports Linux GUI applications through WSLg on supported Windows configurations.

First test whether a simple Linux GUI application works.

Do not modify the GNU Radio installation until the actual error is identified.

19. Lesson 0 Completion Checklist

Mark each item when complete:

[ ] WSL2 installed
[ ] Ubuntu installed
[ ] Ubuntu is running as WSL2
[ ] Ubuntu version checked
[ ] Linux kernel checked
[ ] Python 3 checked
[ ] apt updated
[ ] GNU Radio installed
[ ] GNU Radio version verified
[ ] GNU Radio Python module verified
[ ] GNU Radio Companion launched
[ ] First software-only flowgraph created
[ ] Frequency Sink displays a 100 kHz tone

20. What You Should Understand Before Lesson 1

You should be able to explain:

What is SDR?

A radio architecture in which significant signal-processing functions are implemented digitally/software-based rather than entirely with dedicated analog hardware.

What is GNU Radio?

A framework for constructing DSP and SDR processing systems using connected processing blocks.

What is GNU Radio Companion?

A graphical flowgraph development environment for GNU Radio.

Why WSL2?

It provides a Linux environment suitable for GNU Radio and SDR development while retaining Windows as the host operating system.

What is an IQ sample?

We will answer this rigorously in Lesson 1/2. Do not worry if it is still unclear.

21. Lesson 1 Preview

Next we will study:

GNU Radio Fundamentals

Topics:

Flowgraph
Block
Input/output ports
Stream
Vector
Message
Data types
Sample rate
Complex numbers
IQ representation
Source and Sink
Runtime
Connections

Then we will build increasingly complex flowgraphs.

22. References

GNU Radio

GNU Radio — Linux Installation: https://wiki.gnuradio.org/index.php/LinuxInstall

GNU Radio — Installing GNU Radio: https://wiki.gnuradio.org/index.php/InstallingGR

GNU Radio — Ubuntu Installation: https://wiki.gnuradio.org/index.php/UbuntuInstall

Microsoft WSL

WSL installation: https://learn.microsoft.com/windows/wsl/install

WSL basic commands: https://learn.microsoft.com/en-us/windows/wsl/basic-commands

Connecting USB devices to WSL: https://learn.microsoft.com/en-us/windows/wsl/connect-usb

Instructor Note

This course should progress from concept → mathematics → GNU Radio implementation → measurement → real hardware.

Do not use GNU Radio as a black box.

Every flowgraph should eventually be explainable mathematically and physically:

Physical RF
     ↕
Mathematical model
     ↕
Digital samples
     ↕
GNU Radio blocks
     ↕
Measured result

That is the foundation for using SDR professionally in communications, satellite systems, LoRa, AIS, and other RF applications.

SDR Learning Module — Lesson 0

Preparing the SDR Development Environment with WSL2 + Ubuntu + GNU Radio

1. Learning Objectives

2. What Is Software Defined Radio?

3. What Is GNU Radio?

4. Why WSL2?

5. WSL2 vs Native Windows GNU Radio

6. Lesson 0 Architecture

Stage A — Software-only SDR

Stage B — Real SDR hardware

7. Step 1 — Check WSL

8. Step 2 — Install Ubuntu

9. Step 3 — Verify Ubuntu

10. Step 4 — Install GNU Radio

11. Step 5 — Verify GNU Radio

12. Step 6 — Launch GNU Radio Companion

13. Step 7 — First Flowgraph

14. Step 8 — Understand the First Flowgraph

Signal Source

Throttle

QT GUI Frequency Sink

15. Real SDR Hardware — Later

16. USB SDR Hardware in WSL2

PowerShell

Ubuntu

17. Recommended SDR Software Stack

18. Troubleshooting

Problem A — wsl is not recognized

Problem B — Ubuntu is WSL1

Problem C — GNU Radio package not found

Problem D — gnuradio-companion cannot start

Problem E — GUI problems under WSL

19. Lesson 0 Completion Checklist

20. What You Should Understand Before Lesson 1

What is SDR?

What is GNU Radio?

What is GNU Radio Companion?

Why WSL2?

What is an IQ sample?

21. Lesson 1 Preview

GNU Radio Fundamentals

22. References

GNU Radio

Microsoft WSL

Instructor Note

Problem A — `wsl` is not recognized

Problem D — `gnuradio-companion` cannot start