The HackRF One is a versatile software-defined radio (SDR) capable of transmitting and receiving signals across a wide frequency range (1 MHz to 6 GHz).
While it’s commonly used for signal analysis, transmission, and experimentation, it can also function as a spectrum analyzer—a tool that allows you to visualize and analyze radio frequency (RF) signals in real-time.
In this article, we’ll explore how to use the HackRF One as a spectrum analyzer, the required software, and the best practices for RF signal monitoring.
Table of Contents
What Is a Spectrum Analyzer?
A spectrum analyzer is a device that displays the strength of RF signals across a range of frequencies.
It is commonly used to:
- Identify interference and noise in communication systems
- Analyze WiFi, Bluetooth, cellular, and other RF signals
- Monitor radio transmissions and detect unauthorized broadcasts
- Troubleshoot RF hardware and antenna performance
Traditionally, spectrum analyzers are expensive, but software-defined radios (SDRs) like the HackRF One provide an affordable alternative.
Why Use the HackRF One as a Spectrum Analyzer?
Wide frequency range (1 MHz – 6 GHz) Cost-effective compared to professional spectrum analyzers Open-source software support (GNU Radio, SDR#) Portable and USB-powered for field use
However, the HackRF One has some limitations:
Lower sampling rate (20 MSPS max) than high-end spectrum analyzers Cannot demodulate signals directly without software No real-time sweeping (limited by software and USB bandwidth)
Despite these limitations, it is a powerful tool for spectrum analysis at a fraction of the cost of traditional analyzers.
Software for Using the HackRF One as a Spectrum Analyzer
To use the HackRF as a spectrum analyzer, you need SDR software that supports signal visualization. Below are some of the best options:
SDR# (SDRSharp) – Best for Beginners
- Simple, user-friendly interface
- Real-time spectrum and waterfall display
- Plugins for demodulation and signal processing
Installation:
- Download SDR# from Airspy’s website.
- Install the HackRF drivers using Zadig.
- Open SDR#, select HackRF as the input device, and start scanning.
GQRX – Best for Linux and Mac Users
- Open-source and lightweight
- Works on Linux, Mac, and Windows
- Supports wideband spectrum analysis
Installation:
- Install GQRX via package manager (
sudo apt install gqrx-sdrfor Linux). - Select HackRF One as the input device.
- Tune to your desired frequency range and adjust gain settings.
QSpectrumAnalyzer – Best for Wideband Analysis
- Real-time frequency scanning
- Waterfall and FFT displays
- Works with HackRF, RTL-SDR, and other SDR devices
Installation:
- Install QSpectrumAnalyzer from GitHub.
- Run
qspectrumanalyzerand select HackRF as the SDR source. - Adjust the FFT size and frequency range to fine-tune spectrum resolution.
How to Set Up HackRF One as a Spectrum Analyzer
Step 1: Install Required Drivers
For Windows, use Zadig to install the WinUSB driver for HackRF.
For Linux, install HackRF tools using:
sudo apt install hackrf
Step 2: Connect HackRF to a Suitable Antenna
- Use a wideband antenna for general RF scanning.
- Use a tuned antenna for specific frequency bands (e.g., 2.4 GHz for WiFi).
Step 3: Launch SDR Software
- Open SDR#, GQRX, or QSpectrumAnalyzer.
- Set HackRF as the input device.
- Adjust gain, bandwidth, and sample rate for better resolution.
Step 4: Scan for Signals
- Choose a frequency range (e.g., 88-108 MHz for FM radio, 2.4 GHz for WiFi).
- Observe peaks in the spectrum that indicate active transmissions.
- Use the waterfall display to track signal variations over time.
Best Practices for Spectrum Analysis with HackRF
Use the right antenna – A poor antenna will limit signal detection. Adjust gain settings – Too much gain can cause signal distortion. Select the correct bandwidth – A wider bandwidth captures more signals but reduces resolution. Avoid USB interference – Use a shielded USB cable to reduce noise. Enable waterfall display – Helps visualize signal activity over time.
Common Applications of HackRF as a Spectrum Analyzer
Detecting interference in WiFi, Bluetooth, and cellular networks Scanning for radio transmissions (FM, AM, CB, Ham Radio) Testing RF hardware and antennas Security research and signal monitoring
Final Thoughts
The HackRF One is an affordable and versatile tool for RF spectrum analysis.
While it lacks the real-time speed and precision of dedicated spectrum analyzers, it is an excellent option for hobbyists, security researchers, and engineers who need basic RF signal visualization and analysis.
Related Posts