Foxhole radio used a razor blade for the rectifier, a safety pin and a
#2 pencel led for cat whisker. The Gillette Blue Blade brand got their
color from factory fire hardening which made the surface a
semiconductor. Old stock blades are always available very cheaply on
EBAY, I don't know where in the world else???. Authentic WWII era are
single edge.



http://www.gizmodo.com/archives/imag...adio_planz.jpg



A jerry-rigged transmitter would generate hash up and down the bands,
hopefully the radio police would punish }:-|