• Year
  • 1953
  • Category
  • Commercial Transmitter & Receiver (TRX not Amateur)
  • Radiomuseum.org ID
  • 145568

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

 Technical Specifications

  • Number of Tubes
  • 3
  • Number of Transistors
  • Main principle
  • 3 AF stage(s)
  • Tuned circuits
  • 1 AM circuit(s)
  • Wave bands
  • Wave Bands given in the notes.
  • Power type and voltage
  • AC/DC-set / 110 - 120 Volt
  • Loudspeaker
  • Permanent Magnet Dynamic (PDyn) Loudspeaker (moving coil) / Ø 3.5 inch = 8.9 cm
  • from Radiomuseum.org
  • Model: Twin - Bogen -Presto, David Co., Inc.
  • Shape
  • Tablemodel, with any shape - general.
  • Notes
  • The David Bogen Model Twin is an AC/DC Operated Two or More Station Wireless Intercommunication System.

    The system operates by modulating the AC power line (or GND if using an AC with GND plug) with an Amplitude Modulated (AM) frequency between 160-196kHz.  Therefore, all units must be connected to the same phase AC power line, such as in a single building.  A single slug-tuned oscillator tunes to the desired transmit/receive frequency channel between 160 - 196kHz. (nominal is 175kHz).

    Another independent net of units may also operate on the same AC power line by tuning the first net units to the low end, near 160kHz, and the second net units to the upper end, near 196kHz.

    A "Silent Watchman" mode may be enabled by pressing the Push-to-Talk button down and to the left to lock one unit to the Transmit mode; thus, all other units may continuously and silently listen to that one unit, much like a baby monitor is used today.

  • Author
  • Model page created by Egon Penker. See "Data change" for further contributors.

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