This 12 tube superheterodyne receiver was made in the 1940s by the National Company, Inc. of Malden, Massachusetts. This one includes the matching SC-2-TS 10″ speaker.
It can receive signals in the range of 490 KHz to 30 MHz, covering the 10, 11, 20, 40, and 80 meter amateur radio bands. It has a crystal filter between the 1st detector and the 1st IF Amplifier. The vacuum tubes are; 6SK7: RF Amplifier, 6K8: 1st Detector, 6J5: HF Oscillator, 6K7: 1st IF Amplifier, 6SK7: 2nd IF Amplifier, 6SL7GT: 2nd Detector-Limiter, 5V6; AVC, 6SJ7: BFO, 6SN7GT: Amplifier & Phase Inverter, 2x 6V6: Audio Amplifier, 5Y3G: Rectifier.
The tuning coils are in a large cast assembly at the bottom of the chassis. You pull out the large tuning knob and rotate it to change which of the 6x tuning coils is connected.
