Hem SAQ Forum SAQ Technical Discussions Automatic keying message (aka "wheel") fpr SAQ

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  • #6898 Svara
    Duncan, K2OEQ
    Gäst

    Thank you for keeping SAQ on the air! I just watched the video of the Christmas 2018 transmission. At about 33 to 34 minuets into the video, the continuous tape loop that sends the ”VVV DE SAQ” is shown. I would have expected the tape to be punched in the 2-level ”Wheatstone” system, but it is a 5-level, teletypewriter tape. The tape reader is quite large. Is the tape reader doing a 5-level to CW conversion?

    Did outgoing messages typically come into SAQ via 5-bit teletypewriter signal and then get converter to CW to be sent out over the alternator transmitter?

    Thank you,

    Duncan Brown
    K2OEQ

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    • #8241 Svara
      Karl-Arne Markström
      Gäst

      The Hell ITA2 (Baudot) punched tape to Morse mechanical translators were standard issue at the
      Swedish coast stations for transmitting navigational and weather information over
      the MF telegraphy network. They became phased-out when computer based message
      handling systems were introduced during the late 80s.

      The unit at Grimeton most probably comes
      from Gothenburg Radio/SAG, and is on loan from the Gothenburg Radio Museum.

      73/Karl-Arne SM0AOM
      Formerly systems engineer for the Swedish
      coast radio operations 1981-2010

    • #6904 Svara
      AlexanderSAQ
      Keymaster

      Dear Duncan,
      According to the ”Manual for the telegraph co.” (”Handbok för Telegrafverket”) from 1933, they were using the 2-line Creed-system perforator and punch hole reader at Gothenburg Radio. The signal was then relayed to the Grimeton radio station over the telephone line.
      The Creed system is a further development of the original Wheatstone system.
      At the radio station, we are in the possess of a perforator and punch hole reader from those days, both seems to be for field use.

      The punch hole reader used at our start-up sequence, is a ”Hell” 5-line type, of a more modern style, propably introduced when Morse code was replaced by Telex/Teletype and frequency shift. For example, the radio telegram connection between Sweden (Grimeton) and New York via Tanger, was using this 5-line system however with slightly higher speed (60 Baud) than with Telex/Teletype (50 resp. 45 Baud).

      Regards,
      Fredrik / AlexanderSAQ (with lots of assistance from Ola Hernvall)

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