Thank you to zxkmm, one of the maintainers of PortaPack Mayhem, for writing in and sharing their new program 'SweepSA', a swept spectrum analyzer for Pluto-style AD936x SDRs such as the AntSDR E310 and LibreSDR. It also supports the HackRF One and HackRF Pro, and is designed to feel more like a bench instrument than an SDR receiver app.

One of SweepSA's core features is speed. It uses the AD936x's little-used 'fastlock' feature, which stores synthesizer profiles that can be recalled almost instantly with a full LO retune. The hop, capture, FFT, and detection all run on the board's ARM CPU, so only the reduced spectrum is sent to the PC, which avoids the slow USB or network round trip on every hop. zxkmm reports sweeps of about 10 - 60 ms over a few hundred MHz, and 500 - 800 ms over the full 70 MHz to 6 GHz range. That's similar to a HackRF One, but with each segment a gapless 40 - 56 MHz wide.

Other features include four traces, eight markers, a waterfall, zero span, and CSV/PNG export. Levels are shown in dBFS with an 'UNCAL' badge until an amplitude correction file is loaded. SweepSA is free for Windows, Linux, and macOS (arm64), with downloads available on GitHub. We note that it is currently closed source, but zxkmm plans to publish the source code later.