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Latest update: 6-Mar-2010 (added click on any 3D image  to get full-size/high-resolution image; added link to recording of real Hell-80 transmission)

Update: 4 Jan 2010 (added printout of Hell-80 signals on Feld-Hell); Update: 27 Dec 2009 (added & replaced photos, added 3D photos, articles new); Update: 18 Dec 2009 (added article, manuals and schematics, character-set printout); Update: 18 Sept 2009 (1literature ref added)

©2007-2009 F. Dörenberg. All rights reserved worldwide. No part of this publication may be used without permission from the author. It has taken considerable effort to create these pages. If you "borrow" content from them, at least reference the source.

[overview]       [character set (font)]      [technology]      [characteristics]       [literature]      [3D/stereoscopic photos]

©2004-2010 F. Dörenberg N4SPP

This Hellschreiber, a.k.a. "T typ 80" or simply "Hell-80", is the most modern Hellschreiber produced. It is a military Hellschreiber introduced around 1965, and was used by the Bundeswehr until around 1985. The Hell-80 can be operated in two modes: asynchronous (like the Feld-Hell, but at twice the number of characters per second: 5 cps instead of 2½), and start-stop (like Hell "GL"). Both modes are selectable when operating from the built-in punch tape reader. For keyboard operation, only the start-stop mode is available. As Hell-80 can operate in asynchronous mode, its printer has a two-turn spindle and uses 15 mm wide paper tape (like the Feld-Hell); it also uses the same felt ink roller as the Feld-Hell and Hell "GL". As the Hell-80 was also designed for military field operations, it is referred to as a "Feldfernschreiber" (field-teleprinter), just like the Feld-Hell from the 1930s-1945.

The Hell-80 - front view

The Hell-80 - opened, showing its modular design

Inside of the cover - spare paper rolls and a compartment for spares/accessories

The list of spares/accessories (110/220 Vac power cable, 24 Vdc power cable, transceiver patch cable, soft cotton cloth, dust brush (goat hair!), ink roller set, fuses, rolls of paper tape)

The spares and accessories

The Hell-80 uses a font raster that is slightly different from the one used by the Feld-Hell and the Hell 72/73. The Hell-80 raster is 7x9, rather than 7x14. For start-stop operation, the first column contains a start-pulse, as for the "GL". The binary form of the Hell-80 font is here.

7x9 font of the Hell-80
(the 4-pixel start-pulse in the first column is only used in start-stop mode)

Print-out of the Hell-80 character set

As indicated above, Hell-80 operates at exactly twice the speed of the traditional Feld-Hell. So if you print Hell-80 signals with a Feld-Hell machine (or software), you will see four lines of text instead of two!

Click here for a recording of a real Hell-80 transmissions (both start-stop and synchronous mode). Recorded 1 March 2010 around 7050 kHz. File size: 13 MB.

Hell-80 signals printed with Feld-Hell - tuned to the "mark" tone
(sent with Multipsk, printed with IZ8BLY Hellschreiber running on the same PC)

As Hell-80 is FSK, you can actually select between printing white-on-black and black-on-white ("reverse video"), by tuning to the "black" tone or to the "white" tone (300 Hz shift).
 

Hell-80 signals printed with Feld-Hell - tuned to the "space" tone
 

In addition, when sending Hell-80 in start-stop mode, the start pulse will be printed as well. 

Hell-80 signals printed with Feld-Hell
(sent with Hell-80 machine, printed with IZ8BLY Hellschreiber on PC)

Like the Feld-Hell and Hell-72, the Hell-80 font is stored in non-volatile memory: without power, the memory contents is retained indefinitely. However, the Hell-80 memory is not a mechanical character-drum, but consists of magnetic core memory - a technology dating back to the early 1950s. It uses 35 pairs of small ceramic magnetic rings (the "cores", "Ringkerne"). Several wires are treaded through each of the cores, to provide read/write access. Addressing signals are provided by the decoder-card shown further below.

 

The "Bildpunktregisterkarte" - the pixel-memory card
(also shown in 3D further below)

Schematic of the "Bildpunktregisterkarte"
(click on image for full scale)

The photos below show the decoder card of a Hell-80. It generates a pulse sequence, based on the selected key of the keyboard or the 5-bit code received from the punch tape reader. It contains 16 magnetic cores, and as many switching transistors. The latter are of type OC123, made by Valvo Radioröhrenfabrik GmbH (Philips) in Hamburg. Mullard (UK) also made this type. The OC123 is a germanium bipolar PNP junction transistor, with a max power dissipation of 300 mW, max Ic of 500 mA, a typical static gain h(FE) of 160, max Uce of 50 V, f(T) of 1.5 MHz, and a TO-7 metal case package (h=9 mm, Ø = 8 mm, ≈ 0.3x0.3").

The decoder card ("Decodierer") of the Hell-80 - 16 ceramic magnetic rings
(photo courtesy Remmelt-Jan, PAØRJW)

Close-up of the decoder card
(photo courtesy Remmelt-Jan, PAØRJW)

Here is a summary of the characteristics of the Hell-80: 

	Technology: fully transistorized / solid-state; modular design magnetic core memory for the character font.
	Modulation: two-tone FSK with 300 Hz shift: 1625 Hz (white pixel / no pixel, "space"). When no characters are transmitted for a certain amount of time, the amplitude of the 1625 Hz tone is reduced. 1925 Hz (black pixels, "mark").
	Signaling: 1260 Hz, for remote control of the machine at the opposite station.
	Keyboard: same character set as Hell "GL", with additional characters Ñ Á Ä Ö
	Modes: start-stop (uses start-pulse in first column of character matrix, like Hell-72/73): from built-in punch-tape reader or from keyboard asynchronous (no start-pulse, like Feld-Hell): from punch-tape reader. It is technically possible to use this mode from the keyboard, but few operators achieve sustained 5 cps typing speed. As the paper tape moves fast and continuously, this causes large spaces to appear between printed characters, which is impractical.
	Font raster: 7x9 (vs 7x14 for Feld-Hell and Hell "GL")
	Data rate: 315 baud (3.175 msec minimum pulse width)
	Transmission rate: 5 characters per sec (2x Feld-Hell)
	Telegraphy speed: 50 WPM.
	Channel bandwidth: 2000 Hz recommended (1100 Hz minimum); "necessary bandwidth" per ITU: 800 Hz.
	Duty cycle: 100 % (2-FSK in both asynchronous and in start-stop mode)
	Line interface: 2- and 4-wire
	Allowed signal path attenuation: 35 dB / 4 neper (same as Hell "GL")
	Punch tape reader: built-in. Uses International Telegraphy Alphabet No. 2 (ITA2) standard (5-bit, superseding the 1901 Murray-code and 1874 Baudot-code).
	Remote control: remote (de-)activation via the 1260 Hz signaling tone. Automatically reverts to standby mode if no signals are received for more than 40 sec. the receiving machine can also remote control the sending station, e.g., to stop transmission from punch tape while in start-stop mode. However remote control in this direction requires full duplex operation (4-wire), and is not available during normal communication via radio (unless full duplex via split-frequency operation).
	Power: 21-30 Vdc (24 Vdc nominal. 1.6 Amp nominal) or 110/127/220/240 Vac (±10%), 40-60 Hz. Reduced dissipation when in standby mode (remote activation via tone signaling).
	Weight: 30 kg (≈ 66 lbs)
	Dimensions: 47x51x29 cm (WxDxH)  (≈ 18½ x 20 x 11½ in)

The easiest way to hook up a Hell-80 machine to a transceiver or to the soundcard of a PC is to select "4 Draht Betrieb" (4-wire operation) on the machines interconnect panel. This configures the interface as a 2-wire input plus a separate 2-wire output. The interfaces are transformer-coupled, so no issues with DC offsets. I checked the input and output with my scope, just to be safe. No signal on the input, and 1.8 Vpp on the output ("Sendepegel" (output level) selected to -1 Neper, next to the 2 vs. 4 wire selector button). Obviously this output level needs to be reduced via a simple voltage divider (e.g., a potmeter), before connecting it to the microphone input of a transceiver or PC soundcard (though it is OK for the line-input of a soundcard).

	"Siemens-Hell-Schreiber 80 – Betriebsanleitung Teileliste“, Siemens AG, Bereich Fernschreib- und Datenverkehr, document A22232-A80-A1-1-30, SuW 55097 UN, 270.0,1,  7/1968, 175 pp.; also: Technische Dienstvorschrift TDv 5815/018-13; (Operating manual; 49 MB; low-res file (39 MB) is here).    new
	“Siemens Hell Schreiber 80 – Beschreibung“, Siemens AG, document A22232-A80-A1-1-18, SuW 54232 1268.0,5, 11/1968, 31 pp. (Description; 15 MB)    new
	“Siemens-Hell-Schreiber 80 - Bedienungsanleitung“, Siemens AG, Wernerwerk für Telegrafen- und Signaltechnik, Werksabteilung für Fernschreibgeräte, document A22232-A80-A1-1-19, SuW 54658 UN, 769.0,4, 5/1969, also: technische Dienstvorschrift TDv 5815/018-13; (Operating manual; 39 MB; low-res file (29 MB) is here).    new
	"Siemens Hell Schreiber 80 schematics A1-0-12, A1-6-12, F1-6, L80-N1-8, L80-F21-3-11 [very large format originals (size A0, A1), each scanned as multiple A3 sheets].    new
	"Siemens-Hell-Schreiber 80 Bedienungsanleitung", Siemens AG, April 1967, transcribed by Andrew, SM6MOJ. The Hellschreiber pages of Andrew's website are here
	"The Siemens Hell 80", by Murray Greenman, ZL1BPU (used with permission)
	"Telegrafía Hell: El teletipo Siemens-Hell 80", Jan Smeets (EA3DPB/ ON4ASZ), Radioaficionados (revista de URE), Vol XXXV, April 1984, pp. 232-234 (courtesy Juan Martin/URE)
	”Felldhell op de Hell80”, Arie van Ooijen (PE1AQB), Electron, April 2006, p. 185    new
	“Siemens-Hell-Schreiber 80” [description & characteristics], Siemens & Halske AG, Wernerwerk für Telegrafen- und Signaltechnik, SH 9651, 6 pp., 1960? (courtesy Arie van Oijen, PE1AQB)   new
	“Feldfernschreiber (Siemens-Hell-Schreiber 80) Bedienungsvorschrift Wa T App 80” [operating instructions summary], Siemens & Halske AG, SuW 54656 UN, 769.0.1, 3/68, 2 pp. (1968) (courtesy Arie van Oijen, PE1AQB)   new
	“Hellschrijven”, Reflecties door PA0SE, Dick Rollema (PA0SE), Electron, nr. 8, August 1982, pp. 404-405 (courtesy Gerard Wolthuis, PA3BCB)    new

The 3D/stereoscopic photos below are anaglyphic: you will need a pair of red/green glasses to get the 3D effect. I am not aware of the existence of any other 3D photos (historical or new, like mine) of Hellschreibers. If you know of any, please let me know.

Click on any image to get full size & high-resolution!

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