Last page update: 1 February 2017
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":
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. It was also foreseen to integrate a radio receiver into this electronics unit.
Fig. 2: the portable military "Feldfernschreiber" configuration
(source: adapted from ref. 1)
The anode voltage generator part of the Feldfernschreiber's motor-generator would be replaced with "dry" rectifiers and an electro-mechanical 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 and reliable.
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)
Fig. 3: additional modular configurations
(source: adapted from ref. 1)
After World War 2, 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):
Fig. 4: SH-Geber-Empfänger "T.send.46"
(original unedited photo: © P. Trepte; used with permission)
This configuration is described in detail on the "1940s modular Hell printer-sender system" page.
REFERENCES
- Ref. 1: "Bildpunkschreiberstation, bei der Teile des Gerätes zu Einzelaggregaten sind zusammengefaßt" [modular Hellschreiber station], Rudolf Zimmermann, Wilhelm Heller, Otto Steiner, Siemens & Halske A.G., Reichspatentamt, Patentschrift Nr. 765857, filed: 28-November-1941
- Ref. 2: DC-DC chopper converters
- Ref. 2A: "Wo steht die Wechselrichtertechnik?", H.-J. Wilhelmy, in Funkschau, Jg. 12, Heft 1, January 1939
- Ref. 2B: "Repairing vibrators for DC to DC convertors", Moritz Bickel
- Ref. 2C: "Die elektronische Anodenbatterie", Jochen Jirmann (DB1NV), January 2008, 8 pp.
- Ref. 2D: "Die Wechselrichter und Umrichter, ihre Berechnung und Arbeitsweise" [Zerhacker], Walter Schilling, 27 May 1940, R. Oldenbourg Verlag., 160 pp., OCLC Nr. 6139075
- Ref. 3: in "40 Jahre dpa, Deutsche Presse-Agentur GmbH", Hans Benirschke (ed.), Hamburg 1989, 127 pp.
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