HRO Coils Consumer Models

National Company; Cambridge & Malden (MA)

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  • Year
  • 1934–1964
  • Category
  • Radio part (not a module) 
  • Radiomuseum.org ID
  • 286268
    • alternative name: National Toy Co.
    • Brand: Thrillbox

 Technical Specifications

  • Wave bands
  • Wave Bands given in the notes.
  • Power type and voltage
  • No Power needed
  • Loudspeaker
  • - - No sound reproduction output.
  • Material
  • Metal case
  • from Radiomuseum.org
  • Model: HRO Coils Consumer Models - National Company; Cambridge &
  • Shape
  • Miscellaneous shapes - described under notes.
  • Notes

  • The HRO Coils all had 4 IF cans mounted to a plate that plugged into the radio, but there were some differences.

    Each radio was supplied with 4 coils (A-D), which can be changes to bandspread. (HRO-JR marked JA-JD and cannot be changed to bandspread.). The HRO variants up to the HRO-5 were identified by the frequency stamped on the IF can. The receivers up to the HRO-7 had handles to facilitate removal of coil, and had same 456 IF, so they are often found with various models.

    HRO (1934 referred to as the Protoype): one frame chart; coils A-F available

    HRO Var.1 & Var. 2: two frame charts; coils A-F available

    HRO Var. 3 & Var. 4: two frame charts; coils A-H available

    HRO Var. 5 & Var. 6: two frame charts; coils A-J available

    HRO-5, HRO-5A & HRO-5A1: single metal plate with graphs & coil ID: coils A-J available

    HRO-7: locking; one metal plate with dial calibration chart & coil letter; coils A-AC; 456 IF

    HRO-50 & HRO-50-1: locking; engraved with coil letter & frequencies; coils A-AC; 455 IF

    HRO-60: locking; engraved with coil letter & frequencies; coils A-AD; IF 2010 & 456

    Coil Frequencies
    A 14.0 - 30.0 MHz
    B 7.0 - 14.4 MHz
    C 3.5 - 7.3 MHz
    D 1.7 - 4.0 MHz
    E 0.9 - 2.05 MHz
    F 0.5 - 1.0 MHz
    G 0.175 - 0.400 MHz
    H 0.1 - 0.2 MHz
    J 0.05 - 0.1 MHz
    AA 27.0 - 30 MHz
    AB 25 - 35 MHz
    AC 21.0 - 21.5 MHz
    AD 50 - 54 MHz
  • Author
  • Model page created by Wayne Childress. See "Data change" for further contributors.

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The model HRO Coils is part of the collections of the following members.

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