Echoes it's a radio spectral analysis software for SDR devices, designed for meteor scattering purposes.
The older releases supported only RTL-SDR devices. They are very cheap SDR based on DVB-T TV tuner dongles based on Realtek's
RTL2832U chipset. Starting from 0.50 Echoes embeds SoapySDR allowing the support of many other SDRs.
Echoes doesn't demodulate neither decode any human-made signal. Its main goal is to analyze and record the total power of natural signals and generate screenshots and tabular data (CSV, GNUplot) output in presence of particular peaks in a selected narrow range of frequencies. Since there is no demodulation, there is no provision for audio listening, except for a notify sound when an event has been recorded.