Carrier Sleuth, from small software developer Black Cat Systems, is designed to aid serious hams digging out overpowered medium-wave signals.
It operates as a specialized FFT (up to 32 million points) to generate RF waterfall of signals provided by software-defined radios such as SpectraVue, SdrDx, Perseus, Studio1/SDRUno, ELAD and Sdr-Radio.
Black Cat Systems explains: “While you can often only hear one, or perhaps two, stations on a frequency at a time, chances are there are actually many other stations lurking on that frequency … The problem is that they are too weak to notice using normal listening techniques. There’s no audio, and even their carriers are often quite weak. But by performing very high-resolution FFTs on recordings made by SDRs you can extract these carriers up out of the noise and see them.”
Carrier Sleuth is available for Windows and Mac and is currently free. Black Cat Systems also has a number of fun RF and audio software toys to check.