The Bunnell Mechanical Set No.1 is a very simple mechanism intended to
teach the student to associate a sound with a Morse code character just as
the sound would be heard on a sounder. In fact, that's what the set is:
a sounder with a key knob attached to depress the sounder arm! You could
really just as easily have pushed down on a regular old sounder.
The Bunnell Mechanical Set No.2 is a somewhat more sophisticated device,
with the key knob removed to its own lever arm in line with the sounder.
Both the Bunnell Mechanical Practice Sets have the J.H. Bunnell and Co.
name stamped into the wooden base. Advertisements for the Bunnell practice
sets can be found as late as the 1920's.
This is the A.A. Transmitter, a learning device patented in 1901 by C.S. Comins and
manufactured by the Audible Alphabet Company of Boston, Mass. A perforated tape was cranked
with the small handle through the instrument which then made contact. The device was to be
connected to a battery and sounder to complete the system. Perforated tapes and
an instructional booklet were included.
The Omnigraph was patented by Charles E. Chinnock of Brooklyn, NY,
on October 25, 1904. It was offered by Sears as early as 1902 and
available eventually in a number of styles. This one is a simple
hand cranked mechanism. The hand crank turns the disk which has bumps
around the edge. The bumps close a contact and produce Morse code on
the sounder. The disc on this machine reads: "John quickly extemporized
five tow bags."
Here is a more complicated Omnigraph. The clockwork on the right
drives the discs around instead of a handcrank. The bumps on the disc
are read by a contact point on the left hand side. The contact point
travels up and down the 10-15 discs in a stack by virtue of a heart-shaped
cam. This machine is a real beauty to see in action!
Frank B. Perry and Sons of Newton, Mass. made the "Radio Blinker Signal Set",
patented in 1917. It consists of a strap key on a wooden box which has a buzzer and
light in a metal housing on top. This appears to be one of very few practice sets
intended specifically for training in the new art of wireless.
The Natrometer was made exclusively for the National Radio Institute
of Washington, D.C. It consists of a clockwork-like mechanism underneath
the barrel and copper strips which are individually selected to read the
code at any level on the barrel. There is a key to the right and a buzzer
present at the upper left but behind the clockwork in the photo. As with
the Omnigraph instruments, extra barrels with text were available.
Both the Omnigraph and the Natrometer were predecessors of the Instructograph.
The Instructograph was made from 1947 or earlier to at least up until the late 1950's and was
available with both an electric motor drive with cord and plug, and with
a hand crank and spring drive. These machines read perforated tape which
is drawn across a contact point. They were available with several different
perforated tape rolls and an instruction booklet by O.B. Kirkpatrick. The
Instructograph Company was located in Chicago, IL. early on, but appears
to have later moved to Glendale, CA.
At least 14 different manufacturers made the ubiquitous J-38
during and after WWII. The J-38 is quite properly considered a
training device: it was a classroom training key. The funny "Line"
and "Tel" terminals and the eye-screw attached in series to headphones
and the training switchboard. It was not intended as a working field
key. The surplus market was flooded with J-38s after the war and as
recently as 5 years ago they could be found for about a buck in fleamarkets.
Please see "the Vail Correspondent", No. 10, January 1995, for a
nicely done discussion of this key.
This yellow-flowered plant is the Camphorweed,
better known in the Southwest as the "Telegraph Plant." It grows alongside railroad
tracks and telegraph lines where the soil has been disturbed.
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Here's a great page by Dave Meier (N4MW) with all sorts of code trainers!