Please click your language flag. Bitte Sprachflagge klicken.

HRO Var. 5 (according to Moore)

HRO; National Company; (ID = 1285327) Commercial Re HRO; National Company; (ID = 1985513) Commercial Re
HRO; National Company; (ID = 1985514) Commercial Re HRO; National Company; (ID = 1985515) Commercial Re
HRO; National Company; (ID = 1985516) Commercial Re HRO; National Company; (ID = 1985677) Commercial Re
Use red slider bar for more.
HRO; National Company; (ID = 1285327) Commercial Re
National Company;: HRO [Commercial Re] ID = 1285327 933x518
Select picture or schematic to display from thumbnails on the right and click for download.
For model HRO Var. 5 (according to Moore), National Company; Cambridge & Malden (MA):
Aufnahme von der Ham Radio 2012, Friedrichshafen ZF-Ausgang und Schalter (re, antelle Kopfhörerbuchse) unter S-Meter nicht original.
Country:  United States of America (USA)
Manufacturer / Brand:  National Company; Cambridge & Malden (MA)
alternative name
National Toy Co.
Year: 1943–1945 ? Category: Commercial Receiver (may include amateur bands)
Valves / Tubes 9: 6D6 6D6 6C6 6C6 6D6 6D6 6B7 42 6C6
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 240 Volt
Loudspeaker - This model requires external speaker(s).
Power out 1.5 W (unknown quality)
from Model: HRO [Var. 5 ] - National Company; Cambridge &
Material Metal case
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

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 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.

HRO-model with knobs with metal skirts (selectivity control in right upper corner also with metal skirt), round metal labels around AVC and B+ switches, black micrometer dial and round S-meter, S-meter toggle switch; printed metal calibration charts on coilsets. Usually rectangular IF filter shielding cans.

External "dog house" type power supply : PSU 697 (filaments 6.3 V AC, B+ 240 V DC) used as standard.

This model variant has been used for HRO-5, HRO-M, HRO-W (tropicalised) sets.



Net weight (2.2 lb = 1 kg) 14.5 kg / 31 lb 15 oz (31.938 lb)
Source of data Communications Receivers
Circuit diagram reference Rider's Perpetual, Volume 17 = 1948 and before

Model page created by Martin Bösch. See "Data change" for further contributors.

All listed radios etc. from National Company; Cambridge & Malden (MA)
Here you find 430 models, 275 with images and 162 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.