BTS Short Wave Unit

BTS (B.T.S.) British Television Supplies; London

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  • Year
  • 1935 ?
  • Category
  • Pre-stage (adaptor for SW/FM/VHF/UHF incl. built-in), Frequency converter
  • Radiomuseum.org ID
  • 361753

 Technical Specifications

  • Number of Tubes
  • 1
  • Main principle
  • RF Converter/Adapter (not voltage converter)
  • Wave bands
  • Short Wave (SW only)
  • Power type and voltage
  • Powered by external power supply or a main unit.
  • Loudspeaker
  • - - No sound reproduction output.
  • Material
  • Metal case
  • from Radiomuseum.org
  • Model: BTS Short Wave Unit - BTS B.T.S. British Television
  • Shape
  • Tablemodel without push buttons, Mantel/Midget/Compact up to 14
  • Notes

  • The BTS Short Wave Unit was a versatile shortwave converter designed to expand the reception capabilities of standard broadcast receivers. It enables listeners to tune into both amateur phone transmissions and commercial shortwave broadcasts, greatly increasing the range of stations accessible on a conventional radio set.

    Frequency Coverage

    • Standard Coils: The unit covers wavelengths from 13 to 52 metres, corresponding to the following shortwave bands: 13 m, 16 m, 19 m, 20 m, 25 m, 31 m, 40 m, and 50 m.
    • Optional Coils: Two additional coils are available to extend coverage from 50 to 260 metres, allowing reception of lower-frequency bands.

    Flexibility & Compatibility

    • Adapter Function: The unit can be plugged directly into the detector stage of straight (non-superheterodyne) receivers, effectively converting them for shortwave reception.
    • Superhet Function: It can also serve as a superheterodyne (superhet) converter, positioned ahead of receivers equipped with one or more high-frequency (RF) stages.
    • Triple Detection: When used in conjunction with a superheterodyne receiver, the system achieves triple detection, resulting in exceptionally high efficiency and selectivity.

    Valve Requirements

    • Battery Sets: Requires a PM2DX valve (tube).
    • Mains Receivers: Requires an AC/HL valve.

    Tuning Mechanism

    • Main Tuning: Utilises a single air-dielectric tuning condenser with a very low loss value of 0.00016 uF.
    • Dial Mechanism: Tuning is accomplished via a slow-motion dial with a 180:1 gear ratio, allowing for extremely precise frequency adjustment.
    • Reaction Control: Features a slow-motion reaction condenser for fine-tuning and optimising sensitivity.

    Construction & Usability

    • Screening: The unit is fully screened to minimize the effects of hand capacity (unwanted detuning caused by the proximity of the operator’s hand).
    • Ease of Use: Designed to be as straightforward to operate as a standard broadcast set.
  • Price in first year of sale
  • 2.65 GB £
  • Mentioned in
  • -- Original prospect or advert (Wireless Magazine Jan 1935, Page 571.)
  • Literature/Schematics (1)
  • -- Original prospect or advert (Television & Shortwave World Apr 1936, Page 236)
  • Author
  • Model page created by Gary Cowans. See "Data change" for further contributors.

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