Automatische Schnelltelegraphieanlage (Automatic High Speed Telegraphy System)

Uhren- & Apparatefabrik W. Moser - Baer, Sumiswald

Swiss Army Communication Sets
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Moser-Baer AMS
Moser-Baer UV200a
Moser-Baer MFA
Moser-Baer SL b
Moser-Baer GS200b
Moser-Baer SR200b
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überarbeitet am 21.5.2013

In the fourties, an automatic high speed telegraphy transmitter, which was used by the Swiss Army for morse code training purposes, has been produced by Moser Baer, Sumiswald. The precision mechanics company Moser Baer does still exist nowadays, today the precision mechanics and eletronics company Mobatec and Mobatime, who does produce the famous Swiss railways clocks, are the successors of the original company.
The high speed telegraphy system MFA was introduced with the troops in around 1944.

High Speed Telegraphy System MFA

Morse code transmitter GS 200b
Transmitting head A: 20 - 200 ZpM
Transmitting head B: 100 - 900 ZpM

Printing Unit SR 200b

Tape puncher SL b

In 1939, at the eve of World War II, it turned out, that the signalmen of the Swiss Army were not sufficiently trained to transmit messages with sufficiently high morse code speeds; their training and the receiver Lorenz Eo509/I was suitable to operate the "Hell printers" which were installed on Swiss high power stations.

So the technical responsibles of the Swiss Army Signal Troops decided to introduce automatic high speed morse code transmissions. The equipment was developed by "Moser Bär", a Swiss precision mechanics company who had already produced a telegraphy transmitting system (AMS) using punched paper tapes, which was used for morse code training purposes.
The intended way of operation was that at the transmitter location, the message was converted onto a punched paper tape, this punched paper tape was then inserted into the transmitting head of the transmitter unit and the audio signal could be fed to the transmitter.
At the receiving location, the audio signal coming from the receiver's line out output was fed to the AF input of the printing unit. The morse code was printed on paper tape and the tapes with the messages translated into plain text by another signalman. It turned out that this transcription procedure was also very time consuming as reading morse code from the paper tape and writing it down took the same amount of time es reading the morse code from the headphones.

High speed telegraphy has been introduced with the high power stations M1K, G1,5K as well as the C-Station in around 1944. After it turned out that overall message transmission speeds remained low as the morse code transcription procedure was time consuming, the Swiss Army Signals found that plain morse code transmissions with plaintext written down from the morse code heard in the headphones after a period of intense better morse code teaching and practicing showed better results then the technically advanced high speed telegraphy. Only after the introduction of the ETK plain text printer in the early fifties, automated telegraphy was used successfully with the Swiss Signal Troops.

The high speed telegraphy transmitting system "MFA" has been developed by the precision mechanics company Moser-Baer, Sumiswald. It consists of a tape puncher Sl b, the transmitting unit GS 200b, the printing unit SR 200b and and electro - mechanical paper tape transport unit.
All units have designations with a small letter "b" at the end.

With the tape puncher SL b, which comes in it's own crate (37,0 kg with accessories) and can be powered from 125 - 250 Volts AC, a punched paper tape with the text message is generated.
Moser-Baer SL b
The motor runs with constant speed, the transport head moves the paper tape at constant speed and the punching head punches the transport holes and the holes for the morse code characters.
On the paper tape, there are transport holes in the middle, these are generated, when the space key for a space between two words is depressed. Two holes on both sides of the transport hole in the middle code for a dot and two diagonal holes code for a dash in morse code.
Lochstreifen Moser-Baer Schnelltelegraph

The punched paper tape is inserted in the transmitting head of the transmitting unit, so that the first hole of a line is on top and the second hole is below the transport holes; the operating instructions recommend to mark the beginning of the paper tape with an arrow.
The punched paper tape is transported through the transmitting head. The polarised telegraph relay will close the circuit, when the rear contact pin in the transmitting head will give contact, and it will open the circuit, when the front contact pin makes contact (because there are two opposite holes coding a dot). In case of a dash with two diagnonal holes, the circuit is closed when the rear pin makes contact, the paper tape will be transported one step until the front pin makes contact and the circuit is opened, so a longer signal (a morse code "dash") is generated.
The transmitter GS 200b can be equipped with two different transmitting heads. Transmitting head A is used for morse code practise with 20 - 200 CpM speed and transmitting head B was intended to be used for high speed telegraphy with speeds of 100 - 900 ZpM, the transmitting speed can be regulated
GS 200b Moser-Baer

The Printer Unit (Schreibgerät) SR 200b prints the morse code on a paper tape, the transcription of the morse code to plain text is done manually. A paper tape transport unit can be used to pull the paper tape with variable speed to have the hands free for writing the letters down when decoding a message.
GS 200b Moser-Baer

weitere Lektüre:
d: Moser-Baer equipment at Frank Dörenberg's Hellschreiber website
d: Automatische Schnelltelegraphie - Anlage, Uhren- & Apparatefabrik W. Moser-Baer, Sumiswald

© Martin Bösch 21.5.2013