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Last page update: 1 February 2017


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INTRODUCTION

A 1941 Siemens-Halske patent (ref. 1) proposes a modular "building block" ("Baukasten") Hellschreiber system. At the heart of it is a "printer + motor" unit. This unit can be turned into a stand-alone printer, simply by attaching a vertically oriented paper-tape cassette. Alternatively, a "keyboard-sender + paper tape cassette" unit can be attached, or a "punch-tape sender + paper tape cassette":

Presse hell peripherals

Fig. 1: the modular Siemens-Hell concept

(source: adapted from ref. 1)

The "printer + motor" and "keyboard-sender + paper tape cassette" can be combined into a carrying case, together with an electronics unit ( = amplifier, tone-generator, power-supply). I.e., the next generation Siemens-Hell Feldfernschreiber. The patent actually references the existing Feld-Hell several times. Also, the proposed electronics box (see Fig. 2), has the same connector block on the right-hand side as the "real" Feld-Hell.

Presse hell peripherals

Fig. 2: the portable military "Feldfernschreiber" configuration

(source: adapted from ref. 1)

A radio receiver could also be integrated into this electronics unit. The anode voltage generator part of the Feldfernschreiber's motor-generator would be replaced with "dry" rectifiers and an electromechanical DC-DC converter ("Zerhacker", "Wechselrichter", "Pendelumformer", chopper/vibrator) plus a step-up transformer and rectifier. Ref. 2A-2D. Anode batteries are not exactly practical, and a portable power source is already required for the motor and the vacuum tube filament heating anyway. Chopper-converters were used in a number of Wehrmacht radios. The 100 Hz "Zerhackerpatronen" are light, relatively small, and easily replaceable (like a vacuum tube), though not necessarily very robust.

Obviously, the motor in the printer module drives the printer. It also has two output gears. The one on the right drives the keyboard-sender or punch-tape-sender unit. The one on the left is for driving a callsign-generator module (not detailed in the patent).

The new paper tape cassette module, keyboard module, and electronics module do not appear to have been developed and produced. After the war, there definitely was no market for a new Feld-Hell model...

Several other configurations are foreseen in the patent:

  • stand-alone "printer only" (item 1 in Fig. 3), as a possible replacement for the "Presse-Hell" printers.
  • "printer + punch tape sender" (item 2 in Fig. 3)
  • desktop "printer + keyboard sender" (item 3 in Fig. 3)
Presse hell peripherals

Fig. 3: additional modular configurations

(source: adapted from ref. 1)

At least two of the modules were actually developed and manufactured: the printer module and punch tape sender module. Combined, they form the Siemens-Hell "Geber-Empfänger" ( = sender/printer, configuration 2 in Fig. 3 above):

Presse hell peripherals

Fig. 4: SH-Geber-Empfänger "T.send.46"

(original unedited photo: © P. Trepte; used with permission)

On the front of the punch tape reader on the right, note the start/stop buttons for sending the special E-shaped Feld-Hell pause-character. The Swiss army acquired at least one of these machines. See Fig. 5. It has an additional module on the left of the printer module. Its function is still to be determined; possibly it is the callsign-generator that is mentioned in the patent. On top of it, there is a small switch box, to toggle between sending and receiving via telephone wires. It has binding posts on the back, for wires and banana plugs.

Presse hell peripherals

Fig. 5: "T.send.46" from the Swiss Army, with additional module on the left

(©2016 M. Boesch; used with permission)

Note the black button with green dot at the center of the photo. This is the "Morse" telegraphy key that is taken directly from the Feld-Hell keyboard.

For more details on this machine, see this page.


REFERENCES


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©2004-2016 F. Dörenberg, unless stated otherwise. All rights reserved worldwide. No part of this publication may be used without permission from the author.