• Country
• Great Britain (UK)

• Manufacturer / Brand
• Unknown - CUSTOM BUILT: GB

• Year
• 1900 ??

• Category
• Morse-Equipment & TTY, RTTY, TDD etc.

• Radiomuseum.org ID
• 191883

Click on the schematic thumbnail to request the schematic as a free document.

• Wave bands
• - without

• Power type and voltage
• No Power needed

• Loudspeaker
• - - No sound reproduction output.

• Material
• Metal case

• from Radiomuseum.org
• Model: Double Current Key - Unknown - CUSTOM BUILT: GB

• Shape
• Tablemodel, with any shape - general.

• Dimensions (WHD)
• 120 x 85 x 210 mm / 4.7 x 3.3 x 8.3 inch

• Notes
• This is an elaborate key with a complex mechanism enclosed within a circle. Sent out a weak negative signal between dots and dashes to depolarize very long telegraph lines and counteract the capacitance. When not sending, the operator flipped the switch to "Receive" - allowing messages to be received over the same pair.
  There are several manufactors known, e.g. BI & HC Ltd, Liverpool or the G.P.O. made keys themselves in a works not far from the Silvertown Telegraph Works in London.

• Net weight (2.2 lb = 1 kg)
• 1.6 kg / 3 lb 8.4 oz (3.524 lb)

• Author
• Model page created by Bernd P. Kieck. See "Data change" for further contributors.

• Other Models

• Here you find 117 models, 107 with images and 10 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from Unknown - CUSTOM BUILT: GB