"WAYNE CHIRNSIDE" bravely wrote to "JAY EMRIE" (24 Jan
04  09:48:00)
 --- on the heady topic of "Re: *BIG* TRANSISTORS"

 -=> JAY EMRIE wrote to ROY J. TELLASON <=-

 JE> I can still remember the first radio I built:
 JE> Wound a coil myself, used a lead crystal for a diode and a pair of
 JE> headsets. Of course this was just recently - in 1942!

 WC> I built one of those.
 WC> Quaker oatmeal box coil form.
 WC> Real solderable tin foil peeled from gum wrappers
 WC> for the capacitor.
 WC> Enamaled wire coil on the form with one band stripped of insulation
 WC> and tuned by a sliding contact.
 WC> Crystal holder made of some small piece of rearranged copper
 WC> tubing and gallina Xtal.
 WC> Early 60's in the Boy Scouts.

The toughest part to find these days is the high impedance headphones
or crystal earphones. The galena used to be substituted in the early
20's by some specific brand of safety razor blade. Apparently the
razor blade metal manufacturing underwent a "bluing" process that made
it an ideal rectifier. Probably some type of oxide, in other words a
metal/oxide rectifier. Those had a pretty low junction voltage just as
germanium. The easiest is still to simply use a 1N60A or 1N34 but then
they didn't have those in the 20's.

 Mike
 ****

... KPLA:  Klingon radio:  All glory, all the time!
--- Blue Wave/DOS v2.30