Using the HackRF One as a wideband spectrum analyzer – 0xStubs
The $11 spectrum analyzer & SDR - EDN
An RTL-SDR Spectrum Analyzer | Hackaday
GitHub - xmikos/qspectrumanalyzer: Spectrum analyzer for multiple SDR platforms (PyQtGraph based GUI for soapy_power, hackrf_sweep, rtl_power, rx_power and other backends)
GitHub - demantz/RFAnalyzer: Spectrum Analyzer for Android using the HackRF
SATSAGEN Spectrum Analyzer Software Updated: Now Supports RTL-SDR
Software-Defined Radios
Testing an RTL-SDR Spectrum Analyzer – Kerry D. Wong