WinASA has been used here to display the 19 kHz pilot signal present in the FM receiver audio. This signal is used as a reference for separating left and right channel information.

This image shows the signal in isolation:

Following is the 19 kHz signal in full context of all other audio in a typical FM broadcast received at a great distance. The rising values at lower frequencies and periodics are characteristic of voice and music. The 19 kHz component stands out like a sore thumb. Being unmodulated and separated from other elements of an FM transmission by filtering, it might make a good candidate for detection and analysis of meteor scatter (be sure to scroll right if 19 kHz is not visible on your monitor):