T-R Switch 250-39

Johnson Company, E.F.; Waseca, MN

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  • Year
  • 1963 ??
  • Category
  • Amateur Equipment (Other, but not Key)
  • Radiomuseum.org ID
  • 265988
    • Brand: Viking

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

 Technical Specifications

  • Number of Tubes
  • 2
  • Main principle
  • something special ? Please give information (notes)
  • Wave bands
  • Short Wave (SW only)
  • Power type and voltage
  • Alternating Current supply (AC) / 110-120 Volt
  • Loudspeaker
  • - - No sound reproduction output.
  • Material
  • Metal case
  • from Radiomuseum.org
  • Model: T-R Switch 250-39 - Johnson Company, E.F.; Waseca,
  • Shape
  • Tablemodel without push buttons, Mantel/Midget/Compact up to 14
  • Dimensions (WHD)
  • 4.25 x 4.375 x 5.375 inch / 108 x 111 x 137 mm
  • Notes

  • The E.F. Johnson T-R Switch 250-39 is a compact electronic T-R switch with transmitter pass-through and receiver output, using three SO-239 (UHF) connectors. Power rating 1KW carrier and 4KW PEP. 2-30MHz. Gain 2dB@30MHz, 6dB@3.5MHz. A 6BL7 dual Triode is used as a broadband voltage amplifier followed by Cathode folllower stage which limits output to a separately muted receiver. Instant break-in. Tip jack on panel for monitoring by oscilloscope. It has no external controls.

    Editors notes: This product is designed for use with tube type receivers. Use extreme caution when using a solid state receiver because the RF signal at the receive port may be high enough to damage sensitive transistor inputs of receivers. The user should take steps to control this. The TR switch is intended to be used with the receiver on the same frequency as the transmitter. Because this TR switch is left in-line with the transmitter output and any antenna tuner, the tuning circuits in those equipments may reduce the gain at frequencies to which they are not resonated. On the other hand, the TR switch has a high impedance input and works well as a broadband buffer with gain when no additional resonating circuits are connected. The cabinet normally runs very warm.

  • Net weight (2.2 lb = 1 kg)
  • 4 lb (4 lb 0 oz) / 1.816 kg
  • Price in first year of sale
  • 29.95 USD
  • Author
  • Model page created by Patrick Jankowiak. See "Data change" for further contributors.

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