Manufactured from 1960 to 1964(?), the National NC-190 is a 10-tube double-conversion general coverage receiver with separate band spread scales for the amateur bands and the SWBC bands. As an archived National NC-190 web page states, it is "a receiver with maximum ham band performance, and with the flip of a knob, the only receiver on the market with calibrated foreign broadcast band spread." And when you flip the knob, the band spread tuning dial switches between red numbering displaying the amateur bands and black numbering displaying the SWBC bands.
Main Tuning ranges: 540-1600 kHz, 1.6-4.0 MHz, 4.0-10.0 MHz, 10.0-20.0 MHz, and 20.0-30.0 MHz.
Amateur band spread: 80 Meters (3.5-4.0 MHz), 40 Meters (6.9-7.5 MHz), 20 Meters (13.8-14.5 MHz), 15 Meters (21.0-21.5 MHz), and 10 Meters (26.6-30.0 MHz).
SWBC band spread: 49 Meter Band (5.9-6.3 MHz), 31 Meter Band (8.6-10.0 MHz), 25 Meter Band (11.7-12.0 MHz), 19 Meter Band (14.6-15.4 MHz), 16 Meter Band (16.4-18.0 MHz), and 13 Meter Band (21.5-22.1 MHz).
The NC-190 has a selectivity knob with three bandwidths: 0.6 kHz, 3 kHz, and 5 kHz, and it has BFO tuning for CW and SSB. This set requires an external speaker. The Main Tuning/Band Spread dial knob shown on the set pictured here is not original.