RTL-SDR Wide Spectrum Analyzer
Over on YouTube claudio giuliani has posted a video of his RTL-SDR Wide Spectrum Analyzer software. The software is written in the basic for gambas language and uses an RTL-SDR software defined radio to plot a wide chunk of the frequency spectrum by sweeping over it. It looks to be similar to the RTL-SDR Scanner software. Currently it is only available for Linux.
RTL_SDR Wide spectrum analyzer