HRO-B-Junior HRO-B-JR

National Company; Cambridge & Malden (MA)

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  • Year
  • 1938 ??
  • Category
  • Amateur-Receiver (amateur bands, may include broadcast bands)
  • Radiomuseum.org ID
  • 86423
    • alternative name: National Toy Co.
    • Brand: Thrillbox

 Technical Specifications

  • Number of Tubes
  • 9
  • Main principle
  • Superhet with RF-stage; ZF/IF 456 kHz; 2 AF stage(s)
  • Tuned circuits
  • 11 AM circuit(s)
  • Wave bands
  • Broadcast plus more than 2 Short Wave bands.
  • Power type and voltage
  • Powered by external power supply or a main unit. / AC 6.3 & DC 180 Volt
  • Loudspeaker
  • - This model requires external speaker(s).
  • Power out
  • 1.5 W (unknown quality)
  • Material
  • Metal case
  • from Radiomuseum.org
  • Model: HRO-B-Junior HRO-B-JR - National Company; Cambridge &
  • Shape
  • Boatanchor (heavy military or commercial set >20 kg).
  • Dimensions (WHD)
  • 440 x 220 x 300 mm / 17.3 x 8.7 x 11.8 inch
  • Notes

  • Variant of HRO-JR ( HRO Junior ) lacking crystal filter, S meter anmd bandspread coils, equipped with tubes for battery operation with 180V B+ voltage.

    Coverage : 1.7 – 30 MHz ( 4 standard ganged coil sets for 1.7 – 4, 3.5 – 7.3, 7 – 14.4, 14 – 30 MHz included, 2 coil sets for broadcast immediately available at extra cost, 7 more coil sets sold later including long waves ( total spectrum covered from 50 kHz to 54 MHz ).

    Modes AM/CW/SSB (BFO).

    The 0 – 500 epicyclic readout dial allows for continuous analog tuning while digitally indicating incremental progress over a range of ten full turns of the large tuning knob that tunes with velvet smoothness. Ten times the circumference of the dial is nearly 4 meters on a normal dial scale, which delivers great frequency resolution. The dial is not calibrated, so more used as logging dial, the frequency is determined used printed calibration charts on coil sets.

    External "dog house" powe suppliy used : 686S (to operated from 6V DC, vibrator) or 5897 (filaments 2,5V AC, B+ 230V DC) to run sets equipped with battery valves from mains.

  • Net weight (2.2 lb = 1 kg)
  • 12.5 kg / 27 lb 8.5 oz (27.533 lb)
  • Author
  • Model page created by Martin Bösch. See "Data change" for further contributors.

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