No 2 model' Crystal set Radio Receiver

Crystal set. BBC logo in several places, aerial in the form of a coil on the top. The crystal set was a simple radio receiver which did not need any power to make it work. It only received AM, amplitude modulated, signals. The crystal, with a point contact, called a cats whisker as that was what was sometimes used, on its surface, created a diode action rectifying the carrier wave so making it possible to hear the audio signal which was modulated onto it.