HRO-B

• alternative name: National Toy Co.
• Brand: Thrillbox

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.

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.

The HRO-B (battery model) is identical to Variant 4 (according to Moore), adjusted for maximum performance with a plate voltage (B+) of 180 V. 6,3 Volt D.C. operation with 686S table model of battery power supply with vibrator.

Can be powered alternatively from mains with the 5886 (filaments 6,3 V AC, B+ 180 V DC) power supply.

In questo link sono elencati 446 modelli, di cui 285 con immagini e 189 con schemi.
Elenco delle radio e altri apparecchi della National Company; Cambridge & Malden (MA)