[GreenKeys] Boehme

[Jim Haynes]

Boehme is known primarily as a manufacturer of equipment for high speed
Morse telegraphy.  This was transmitted from punched paper tape at a speed
of 500 wpm or so and received on an ink recorder.  Then operators
transcribed the messages by reading the inked tape and typing on a
typewriter.  Transmission was by radio using make-and-break or FSK.

There is a document "The_Art_&_Skill_of_Radio-Telegraphy" (google for
it) and in an appendix is some mention of use of this technology by
the U.S. Army prior to WW-II.  There is an Army manual TM 11-377,
"Boehme Automatic Keying and Recording Equipment" which describes this
stuff, but not the 5-C demodulator.  It shows an earlier demodulator
intended for make-and-break keying only.

I have one of the 5-C units and got a manual on it from WA5CAB.
(but I can't lay my hands on it right now)  There is another similar
unit, made by somebody else and with slightly different capabilities.
This is the CV-305/U.

I haven't tried it, but would opine that it is marginally useful
for RTTY reception.  Marginally because it is really designed for
very high speeds, and very wide shifts, up to 15 KHz.  While it is
adjustable for lower speeds and narrower shift it is getting near
the limit of its capabilities for modern 170 Hz shift operation.

If you have access to ARRL Handbooks from the 1940s and 1950s you'll
find advertising in the back by the T. R. McElroy Co. of Boston.
This company manufactured equipment for high-speed Morse and also
sold equipment manufactured by others such as Boehme.  They also
made equipment for code practice transmissions at normal copy-by-ear
speeds.  There is a biography of Ted McElroy by Tom French which
includes some information about the company and its products.

And that about exhausts my knowledge of the subject.  When I was a 
youngster back in the 1940s I used to tune the shortwave BC receiver
around and would hear these extremely strong, droning signals. My
uncle told me that was high speed Morse, so maybe that's what I was
hearing.

Jim W6JVE


jhhaynes at earthlink dot net