====== Hellschreiber 41 ======
**Hellschreiber 41** with the Hell printer **T. empf. 14**; manufactured by [[Siemens|Siemens & Halske, Berlin]].

The [[Hellschreiber]] or the teleprinter according to R. Hell was developed by Rudolf Hell in 1929; the Hell-Schreiber systems sold by Siemens were accepted with enthousiasm, especially in press and commercial radio.

The text messages in the form of a punched paper tape are converted by the Hell generator into a grid of 7 x 7 pixels and this signal is fed to the transmitter as a pulse sequence. In the radio receiver, the audio pulses are amplified and fed to a printer, which uses a writing spindle to print the message in duplicate on a paper tape.

{{:images:endgeraete-siemens-hell-41.jpg?direct&600|Siemens Hellschreiber 41}}
===== Technical data =====
  * Principle]]: Teleprinter
  * [[Operation modes]]: [[Hell]] (quasi-facsimile system according to Dr Rudolf Hell)

==== Power supply ====
  * [[Mains operation]]: 220 V AC mains

==== Dimensions ====

==== Accessories ====

===== System components =====
The Hell system consists of a "[[Hellschreiber 41 - Lochstreifenstanzer|Hand punch]]", into which the message is typed to create suitable punched paper tapes.\\ 
[[Hellschreiber 41 - Lochstreifenstanzer|{{:images:endgeraete-siemens-hell-lochstanzer-front.jpg?direct&400 |Siemens Hell: Hand punch}}]]\\ 

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The various components are connected to the **transmitter-side power connection box** and can be switched on from a central power switch.\\ 
{{:images:endgeraete-siemens-hell-netzanschluss-senderseitig.jpg?direct&300|Mains power distribution box, transmitter side}}

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The punched tape reader reads the punched tape and generates the Hell signal.

{{:images:endgeraete-siemens-hell-geber-bw.jpg?direct&400|Siemens Hell: punched tape reader}}

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An audio-frequency of 900 Hz from the [[Hellschreiber 41 - Röhrensummer|Röhrensummer]] **T. Sum. 5a** (AF generator) is superimposed to the signal from the punched tape reader, the Hell signal is fed to the transmitter. Keying of the transmitter is done at the grid of the keying valve by on-off keying of the carrier wave.

{{:images:endgeraete-siemens-hell-rohrsummer-t-sum-5a-front.jpg?direct&500|Röhrensummer T Sum 5a}}

----
On the side of the **receiving station**, all the components are also plugged into a wooden power distribution box and can be switched on together.\\ 
{{:images:endgeraete-siemens-hell-netzanschluss-empfaengerseitig.jpg?direct&300|Mains power distribution box}}

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**On the receiver side**, the audio-frequency signal must be amplified (in the [[Hellschreiber 41 - Empfangstastgerät|Amplifier]] **T. Verst. 18a**) and is fed to the Hell printer.\\ 
{{:images:endgeraete-siemens-hell-verstaerker-t-verst-18a-front.jpg?direct&500|Amlifier T Verst 18 a}}

----
In the [[Hellschreiber 41 - Schreiber|Hell Printer]] **T. Empf. 14** a double screw is pulled by electromagnets to print the characters on the slowly moving paper strip.\\ 
{{:images:endgeraete-siemens-hell-schreiber-t-empf-14-front.jpg?direct&400|Hell printer T Empf 14}}

If the speed is poorly synchronised, the two printouts of the message run at an angle, but the message itself remains legible. The synchronisation can be adjusted with the speed control until the two print strips run exactly parallel indicating optimum synchronisation.\\ 
{{:images:endgeraete-siemens-hell-streifen.jpg?direct&400|Siemens Hell: Streifen}}

===== Technical principle =====
Character transmission in a quasi-facsimile process with 7 x 7 pixels.

==== Tube assembly ====
  * in the **tube buzzer T. Sum. 5a**: one [[EDD11]], one fuse 300 mA
  * in the **receiver amplifier T. Verst. 18a**: one [[AF7]], one [[AL4]], one rectifier [[AZ1]], one fuse 300 mA

==== Development ====
The sets developed by engineer Rudolph Hell were manufactured by [[Siemens|Siemens & Halske, Berlin]] and sold for the civilian market.

==== Use ====
From the high power radio station [[SE-302|G1.5K]], the stations from serial number 15 onwards were equipped with the **Hellschreiber 41**, of which 13 systems were acquired. the system consists of two crates and the paper tape punch.

{{gallery>:images?endgeraete-siemens-hell-schreiber-t-empf-14*.jpg&0&80x80&lightbox&showtitle&titlesort}}
===== Technical documentation =====
  * [[https://hamfu.ch/_upload/Siemens-Siemens-Hell-Schreiber_Tempf14-1946-web.pdf|Siemens Hell Schreiber T.empf.14, Siemens & Halske]]
==== Further information ====
  * [[http://armyradio.ch/radio-d/siemens-hell-schreiber.htm|Siemens Hell Schreiber 36 / 41 at www.armyradio.ch]]
  * [[https://www.hamfu.ch/de/geraete/geraet.php?id=128|Siemens Hell Schreiber on the Hamfu website]]
  * [[https://www.nonstopsystems.com/radio/hellschreiber-presse-hell.htm|Siemens Hell Schreiber T.12b and T14]] on the website of Frank Dörenberg