Thank you to Andrey for submitting news about the release of his new open source program called "rtlSpectrum". rtlSpectrum is a GUI for rtl_power, which allows you to scan a wide swath of bandwidth with an RTL-SDR dongle. The scan can then be plotted with rtlSpectrum, and peaks of activity can then be determined. Some of the features include:
- load from .csv file produced by rtl_power
- run rtl_power directly. it should be available in the $PATH
- add multiple graphs for analysis
- subtract one graph from another
- save/export graph in the rtl_power based format
In particular, the ability to subtract one graph from another is useful for analyzing filters. Andrey has posted about doing this with rtlSpectrum, a noise source and an RTL-SDR V3 over on his blog (note that the blog is in Russian, so please use Google Translate if necessary). He notes how the dynamic range of the RTL-SDR is limited, so that the true blocking power of a filter cannot be determined, but it is enough to see the shape and frequency response.