Here is an excellent YouTube video from RimstarOrg that breaks down the concept of how crystal radios actually DO their magic! Yes, MAGIC. Radio signals are all around us 24 hours a day. Invisible! You can’t really touch them. You can’t smell them. You can’t hear them without assistance. We don’t really feel them bombarding us. We don’t sense those signals without some mechanical help… but they strike us with many different frequencies constantly… so let’s explore the range of frequencies we can decipher with a homemade crystal radio set!