HRO Var.4 (according to Moore)
- United States of America (USA)
- Manufacturer / Brand
- National Company; Cambridge & Malden (MA)
- 1938–1943 ?
- Commercial Receiver (may include amateur bands)
- Radiomuseum.org ID
- alternative name: National Toy Co.
- Brand: Thrillbox
Click on the schematic thumbnail to request the schematic as a free document.
- Number of Tubes
- Main principle
- Superhet with RF-stage; ZF/IF 456 kHz; 2 AF stage(s)
- Tuned circuits
- 11 AM circuit(s)
- Wave bands
- Broadcast, Long Wave and more than two Short Wave bands.
- Power type and voltage
- Powered by external power supply or a main unit. / AC 6.3 & DC 180-240 Volt
- - This model requires external speaker(s).
- Power out
- 1.5 W (unknown quality)
- Metal case
- from Radiomuseum.org
- Model: HRO [Var.4 ] - National Company; Cambridge &
- 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
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 Additional coils (50-100, 100-200, 180-430, 480-960 and 900-2050 kHz) sold later including long waves and up to VHF ( 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 to directly indicate a frequency but a frequency calibration chart is necessary to determine the correct operation frequency.
Bar knobs with metal skirts, S-meter toggle switch, red pilot light left of selectivity control, black bakelite epicyclic dial, usually rectangular IF filter shielding cans.
- Net weight (2.2 lb = 1 kg)
- 14.5 kg / 31 lb 15 oz (31.938 lb)
- Price in first year of sale
- 329.00 $
- Source of data
- Communications Receivers
- Mentioned in
- - - Manufacturers Literature
- Literature/Schematics (1)
- Electronics Australia November 1990, Page 110
- Model page created by Martin Bösch. See "Data change" for further contributors.
- Other Models
Here you find 430 models, 278 with images and 165 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
All listed radios etc. from National Company; Cambridge & Malden (MA)