Hallicrafters S-20 Sky Champion
Single conversion 8 tube general coverage receiver. Covers 540KHz to 44 MHz in 4 bands. Compare the silver-color dial to the S-19R. An introductory ad for the S-20 appears in the July 1938 Radio News inside back cover. Price was $49.50 The last Radio News ad for the S-20 appears in January 1939. The S-20 was replaced by the S-20R in late 1939 (the introductory Radio News ad for the S-20R is the back cover of the January 1940 issue.)
Given its short manufacturing run, the S-20 is much rarer than the S-20R. The S-20 uses primarily dual-ended tubes (tubes with grid caps) while the S-20R uses single-ended tubes. The S-20, with single knob tuning, uses mechanical bandspread. The S-20R uses electrical bandspread as indicated by the separate bandspread knob. The "meter" in the center, like other Hallicrafters models of the era, is the bandspread scale.