Thanks to Dave’s post on satellites ( Scanning Horizons ) my wife and I went out this evening and watched the International Space Station go over. It is such an impressive sight…bright, fast, silent.
Then I got an email from my older son with the url to this: Stan Nelson, a ham radio operator from Roswell, New Mexico has recorded a radar signal reflected off the ISS. The spectrogram, shown above and reminiscent of my spectrograms of diesel trucks, shows the doppler shift of the reflected radar signal. He also includes the audio so you can actually hear the shift as the station passes overhead. Check it out at http://www.spaceweather.com/archive.php?view=1&day=02&month=04&year=2009 .