Listening to satellites
The sound of satellites can not be heard by our ears. However using complicated (or less complicated) electronics, we are capable of converting the signals into sound and pictures. How does the sound of a satellite looks like? I think it is beautiful. A perfect frequency shift, due to the motion of the satellite with respect to the receiving station. This figure is in the time-frequency domain, after I did a Fourier transformation on the .wav signal. Time runs from bottom to top and the frequency scale is inverted, just to make life easy. We did not know if the satellite would still be alive when we set up the equipment. But when it crossed the horizon, we heard the signal emerge from the noise. There it was, a piece of space junk that was launched a few years ago, still transmitting its daily data. A coded beeping sound, sending data about the status of its tiny solar cells and other components. We tried to tune another radio such that we could actually listen to the sign