Actually, I'm pretty sure the crystal set you are referring to used a
piece of galena (a lead sulphide compound), not germanium (and not
geranium, which is a flower). Early crystal sets used a piece of
springy wire called a "cat whisker" to contact the galena at a sometimes
difficult-to-locate crystal, in essence forming a crude point contact
(i.e., Schottky) diode. The crystals are small but naturally occurring
in the galena. My dad had such a set and I remember using it when I was
about six or seven years old (60 years ago for me), but by that time
actual germanium diodes were available and my first "real" radio used
one of those.
73,
Dave AB7E
On 7/25/2013 12:22 AM, Chuck Smallhouse wrote:
My first experience hearing local AM stations was using an actual
chunk of geranium crystal mounted in a blob of lead, that you'd traded
some of your best agate marbles for, You used the point of a fine
safety pin to scratch around on that chunk of geranium to find the
sweat spot, where the station (s) came in the best into your
headphones. It didn't seem to be the same spot night after night !
You tried to use the longest wire that you could sneak out your window
and up to near the top of the tallest tree in your back yard.
Later if you wanted to separate KVOA (1290) ad KTUC (1400), here in
Tucson, you had to wind a big coil on an empty round oatmeal box, and
try and tune it with a variable capacitor that you'd "rescued" from a
defunct radio. This was all mounted on a "bread board", generally a
short section of a 1x 6" or a 1x 8"pine or redwood board. Terminal
points were metal screws into the board (preferably brass) that the
wires were wrapped around !
Gee, that was well over 70 years ago ! Time sure flies when you are
having fun !
Chuck,. W7CS
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