M4B blue

Roberts Radio Co.Ltd., East Molesey, Surrey, UK

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  • Year
  • 1936
  • Category
  • Broadcast Receiver - or past WW2 Tuner
  • Radiomuseum.org ID
  • 78649

 Technical Specifications

  • Number of Tubes
  • 4
  • Valves / Tubes
  • Main principle
  • TRF with regeneration
  • Wave bands
  • Broadcast (MW) and Long Wave.
  • Power type and voltage
  • Storage and/or dry batteries
  • Loudspeaker
  • -Loudspeaker incorporated, but system not known. / Ø 6.5 inch = 16.5 cm
  • Material
  • Leather / canvas / plastic - over other material
  • from Radiomuseum.org
  • Model: M4B [blue] - Roberts Radio Co.Ltd., East
  • Dimensions (WHD)
  • 11.5 x 8 x 11.75 inch / 292 x 203 x 298 mm
  • Notes

  • Model M4B.

    Waveranges:

    • 200-550 metres;
    • 1000-2000 metres

    Circuit: Pentode RF amplifier; triode detector with reaction; triode driver valve; Class B output stage. Battery grid bias.

    A compact receiver chassis enables a standard type of HT battery and 20AH accumulator to be used in this suitcase portable.
    The tuning scale is calibrated both in wavelengths and stations, and the 6” diameter loudspeaker is mounted in the lid of the cabinet.

    Selling for 9gns in 1938.

    Leatherette-covered plywood case. Claimed to be the smallest type of portable on the market at the time. Also a black variant.

     

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