A germanium diode is used as the detector in the series-fed version.
|Permeability-tuned Crystal Radio - series-fed version|
For the shunt-fed version it's a germanium transistor (with its base and emitter interconnected).
|Permeability-tuned Crystal Radio - shunt-fed version|
An empty glue stick and a ferrite toroid are used for the tuning mechanism.
The toroid is fixed to the blue glue stick carrier using rubber adhesive. The coil is 60 turns of 30 SWG enamelled copper wire, close-wound on a homebrewed 1" diameter paper former which fits tightly on the glue stick body.
|Tuning mechanism for Permeability-tuned Crystal Radio|
Junk-box parts are used to assemble and wire the radio using a scrap wall wart enclosure as the base.
|Permeability-tuned Crystal Radio Assembly|
Reception of the local 612 kHz, 200 kW AM broadcast station quite good with just a 60' random-wire antenna.