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HRO-50-1; National Company; (ID = 386955) Amateur-R
HRO-50-1; National Company; (ID = 386956) Amateur-R
HRO-50-1; National Company; (ID = 386957) Amateur-R
HRO-50-1; National Company; (ID = 2054694) Amateur-R
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HRO-50-1; National Company; (ID = 2054694) Amateur-R
National Company;: HRO-50-1 [Amateur-R] ID = 2054694 1400x602
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For model HRO-50-1, National Company; Cambridge & Malden (MA):
National HRO-50-1 Instruction Manual
Country:  United States of America (USA)
Manufacturer / Brand:  National Company; Cambridge & Malden (MA)
alternative name
National Toy Co.
Year: 1951/1952 Category: Amateur-Receiver (amateur bands, may include broadcast bands)
Valves / Tubes 15: 6BA6 6BA6 6BE6 6C4 6K7 6SG7 6SG7 6J7 6H6 6SN7GT 6H6 6SJ7 6V6GT 6V6GT 5V4G 0B2
Main principle Superhet with RF-stage; ZF/IF 455 kHz
Wave bands Broadcast, Long Wave and more than two Short Wave bands.
Power type and voltage Alternating Current supply (AC) / 110-120 / 220-240 Volt
Loudspeaker - For headphones or amp.
Power out 8 W (unknown quality)
from Model: HRO-50-1 - National Company; Cambridge &
Material Metal case
Shape Boatanchor (heavy military or commercial set >20 kg).
Dimensions (WHD) 501 x 257 x 420 mm / 19.7 x 10.1 x 16.5 inch
Notes coverage 0,05 - 30 MHz (9 coil sets 50-100 / 100-200 / 180-430 / 480-960 / 900-2050 kHz / 1,7-4 / 3,5-7,3 / 7-14,4 / 14-30 MHz, bandspread in HAM bands), AM/CW/SSB (BFO); improved model of HRO-50 with one IF stage added and cascaded IF transformers; internal power supply, optional external speaker HRO-50TS, optional crystal calibrator XCU-50-2, optional narrow band FM - adapter NFM-83-50.
External source of data Ernst Erb
Source of data Shortwave Receivers - Past & Present (3rd ed.)
Circuit diagram reference Rider's Perpetual, Volume 22, covering 1951

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.