Wavemeter - Modulation Indicator 380 (77)

Simpson Electric Co.; Chicago, IL - Lac du Flambeau, WI

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  • Year
  • 1948
  • Category
  • Service- or Lab Equipment
  • Radiomuseum.org ID
  • 96993

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

 Technical Specifications

  • Number of Transistors
  • Semiconductors
  • 1N34
  • Main principle
  • Crystal or Solid State Detector
  • Wave bands
  • Short Wave (SW) and FM or UHF.
  • Power type and voltage
  • No Power needed
  • Loudspeaker
  • - only for Earphone!
  • Material
  • Metal case
  • from Radiomuseum.org
  • Model: Wavemeter - Modulation Indicator 380 - Simpson Electric Co.; Chicago,
  • Shape
  • Very small Portable or Pocket-Set (Handheld) < 8 inch.
  • Dimensions (WHD)
  • 3 x 5.8 x 2.5 inch / 76 x 147 x 64 mm
  • Notes

  • Band-spread wavemeter and 0 - 100 microammeter as resonance indicator. Calibration charts included.

    • separate plug-in coils for 10, 20, 40 and 80 meter bands supplied, coils for other bands available as option.
    • direct-reading Percentage Modulation Indicator with the instrument calibrated at 0 - 110 % modulation
    • designed to function on the 144, 235, 420 megacycle bands without coils but with quarter wave antenna section
    • used as field-strength indicator
    • one copper oxide recitifier, one diode.

    Price in 1948, dealer's net, including 4 coils, 2 ft. antenna.
    Optional leatherette carrying case, same, $6.75 USD.

    Marketed in Canada as Model 77.

    Note that there are two distinct versions of this meter.  The early version used plug-in coils which had three pins.  The later version used plug in coils with only two pins.  It also has an additiona socket on the meter housing. 
    The older 3-pin coil style has been in existance since at least 1948 (based on a calibration card published in the Jul/Aug 2016 edition of "The Canadian Amateur" , while the later style appears to have been introduced around 1954 or so (based on an ad in the Nov/Dec 1954 issue of "Electronics and Commications".

    The later version is also capable of being used all the way upto 170 MHz. According to the manual (which is available on Archive.org), "two coils for the 6 and 160 meter bands are available. For the two meter band, a calibrated sliding antenna providing tuning facilities from 140 to 170 megacycles is also stocked as an extra item".

  • Net weight (2.2 lb = 1 kg)
  • 2 lb (2 lb 0 oz) / 0.908 kg
  • Price in first year of sale
  • 37.85 USD
  • Mentioned in
  • -- Original prospect or advert (Catalog 1951)
  • Literature/Schematics (1)
  • 1951 Newark catalog Nº 51
  • Literature/Schematics (2)
  • - - Manufacturers Literature (User Manual)
  • Literature/Schematics (3)
  • QST (Oct. 1948, page 79; Nov. 1948, page 124 "NEW SIMPSON MODEL 380")
  • Author
  • Model page created by Vitor Oliveira. See "Data change" for further contributors.

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