St. J Wireless Codegraph

St. John, Thomas M.; East Windham, NY

Data
Forum
Pictures
Collections

  • Year
  • 1912 ??
  • Category
  • Morse-Equipment & TTY, RTTY, TDD etc.
  • Radiomuseum.org ID
  • 340376

 Technical Specifications

  • Wave bands
  • - without
  • Loudspeaker
  • - - No sound reproduction output.
  • Material
  • Various materials
  • from Radiomuseum.org
  • Model: St. J Wireless Codegraph - St. John, Thomas M.; East
  • Shape
  • Miscellaneous shapes - described under notes.
  • Dimensions (WHD)
  • 6 x 3 x 11 inch / 152 x 76 x 279 mm
  • Notes

  • This item was produced as an aid to learning Morse code. It was patented on August 13, 1912  (US patent 1,035,257) to Thomas M. St. John of New York. It consists of a nickel-plated brass plate mounted on a wood backing, with a binding post on the upper left-hand corner. Areas of bare metal were exposed to form the code characters, with painted areas providing electrical insulation. The device was used with a battery and buzzer, and transmitted characters were formed by dragging a metal stylus across its surface to make and break electrical contact. Note that the first line (A-G) has a separate metal strip applied over the original line. This was to correct an error for the letter "C", which was originally specified as    dash dash dot dot (_ _ . .), then corrected to   dash dot dash dot (_ . _ .).

  • Net weight (2.2 lb = 1 kg)
  • 0 lb 4 oz (0.25 lb) / 0.114 kg
  • Mentioned in
  • The Antique Wireless Association Review, Volume 19, 2006, "Morse Code Training Devices" pg. 157
  • Literature/Schematics (1)
  • Patent (US patent No. 1,035,257 Patented Aug. 13, 1912)
  • Author
  • Model page created by Gary Berg. See "Data change" for further contributors.

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The model St. J Wireless Codegraph is part of the collections of the following members.

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