• Country
• Great Britain (UK)

• Manufacturer / Brand
• MIM, Marconi International Marine; Chelmsford Essex

• Year
• 1930 ??

• Category
• Commercial Receiver (may include amateur bands)

• Radiomuseum.org ID
• 257258

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

• Number of Tubes
• 1

• Valves / Tubes

• Wave bands
• Wave Bands given in the notes.

• Power type and voltage
• Storage and/or dry batteries / 2 or 4 or 6 & 72 Volt

• Loudspeaker
• - - No sound reproduction output.

• Material
• Metal case

• from Radiomuseum.org
• Model: Heterodyne Local Oscillator 357 - MIM, Marconi International

• Shape
• Boatanchor (heavy military or commercial set >20 kg).

• Notes

• The heterodyne type 357 has been specially designed for use with the receiver Type 352. It covers a wave range from 200 to 22,000 meters in 5 wavebands and is for use on CW signals only.

  The heterodyne uses a simple oscillator circuit which is coupled to the receiver by means of a coupling capacity, contained within the device. A large HT choke and a decoupling condenser prevent feedback to the receiver via the battery or battery leads.

  The heterodyne comes with a calibration chart that gives instructions about wave range switch and tuning condenser position for each desired wave length.

• Mentioned in
• - - Manufacturers Literature

• Other Models

• Here you find 19 models, 17 with images and 7 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from MIM, Marconi International Marine; Chelmsford Essex