Wave bye bye...

Have you ever thought to try to record your microwave? Theoretically any electro-magnetic wave can be recorded in a digital file with a digital recording device you can get from the store. Ultra sonic waves, supersonic waves... It depends on the software to be able to interpret the recording into readable histographs, and the you may even be able to tell what type of wave it is, but at least you can know what part of the wave falls on your device's ability to record it.