[Elecraft] first keyer

[Joe-aa4nn]

First keyers... remember the Mon-Key?
A pair of dual triode 12AU7s.  One triode
of one tube produced dits while the other
produced dahs using a multivibrator circuit.
The other tube, one triode drove a speaker
while the other drove a keying relay.

Dits and dahs were not self-completing, so
it was tricky to hold the dah paddle down
until the timing was completed, otherwise
a zero might come out as a nine.

de Joe, aa4nn