A big thanks to Simon at SDRradio.com for his release and continual tweaking of a useful tool that comes bundled with the SDR-Radio.com V2 suite known as the SDR File Analyzer (for 64 bit Windows machines only). Here’s a spectrogram showing a variety of AM signals present over a course of 6-1/2 hours on 1710 kHz New Year’s Eve 2012 generated by feeding my Perseus .wav files into the File Analyzer tool. The strong AM carrier in the center belongs to The Big Q which signed off between 1030-1100 UTC. The moment of sign-off is quite obvious on the image. Carrier drift is also interesting to visually examine.