Gqrx SDR — Interactive RF Spectrum Analyzer & Receiver

Gqrx is an open-source software-defined radio receiver powered by GNU Radio and the Qt graphical toolkit. In TelcoChisel, Gqrx is configured out-of-the-box with drivers for all supported SDR hardware (HackRF One, RTL-SDR v4, LimeSDR, BladeRF 2.0 micro, Ettus USRP), allowing researchers to sweep cellular frequency bands, capture IQ data, and demodulate analog and digital transmissions.

Key Capabilities

• Real-Time FFT Waterfall & Spectrum Scope: Visual inspection of cellular downlink/uplink carriers across 2G, 3G, 4G LTE, and 5G NR FR1 bands.
• IQ Recording to Disk: Capture raw complex IQ samples with timestamping for post-processing in Inspectrum and URH.
• AM/FM/SSB Demodulation & Audio Streaming: Live demodulation of analog signals and audio routing via ALSA / PulseAudio.

Cheatsheet

1. Launch Gqrx with HackRF One

# Launch Gqrx GUI
gqrx

2. Capture IQ Samples to RAM Disk

# Record 10 MHz bandwidth IQ stream directly to tmpfs for fast IO
# Trigger via Gqrx UI "Record IQ" button -> /dev/shm/cell_capture.raw

Practice in TelcoSec Academy

👉 Access SDR & RF Signal Analysis Labs at App.TelcoSec.Net