Precision Cast XL Galena Crystal Radio Radio Detector Diode in Low Temp Casting

Description

Precision Cast Galena Crystal Radio Crystal Radio Diode
Cast in Low temp alloy
Actual Galena Crystal Received may vary in Size and Shape
Dimensions are .750 Diameter and .30-.40 tall
Galena Crystal Detector
Crystal mounted and Cast in Low temp alloy to prevent any Crystal damage
Dimensions are .750 Diameter and .30-.40 tall measured from the bottom of the casting to the top of the crystal.
Casting alloy is made from Lead ,Tin and Bismuth and is Cadmium Free
FACTS ABOUT OLD SCHOOL CRYSTAL DIODES
Not every contact position on the Galena crystal will perform, so fiddling with the ‘cat's whisker’ to find a sweet spot does take patience and skill.
Cat Whisker:
The "cat whisker", a springy piece of thin metal wire, formed the metal side of the junction. Phosphor bronze wire of about 30 gauge was commonly used because it had the right amount of springiness.
Cat whisker detector:
It consisted of a pea-size piece of crystalline mineral in a metal holder, with its surface touched by a fine metal wire or needle (the "cat whisker"). The contact between the tip of the wire and the surface of the crystal formed a crude unstable point-contact metal–semiconductor junction, forming a diode. The wire whisker is the anode, and the crystal is the cathode; current can flow from the wire into the crystal but not in the other direction.
Having a lot of patience and a steady hand are needed when you listen with a piece of the rock. But this can also be very rewarding when you can hear the first station using a cats whisker detector.