A recent thread at rec.antiques.radio+phono:
http://groups.google.com/group/rec.a...a7aa08a09859bd
uncovered that some radios made in 1940 had the notation "TV Sound" on the tuning dial on the shortwave band at just above 8 mHz. Philco made a "television converter" in 1940 which broadcast the audio IF (8.25 mHz) to a nearby radio receiver, thus eliminating the need for an audio detector, amplifier, and output tube:
http://www.earlytelevision.org/philc...html#converter
The notations have been discovered on Sears/Silvertone models 6436 and 6490. Probably 1940 model Philco radios have similar notations.
If you have a radio with TV Sound on the SW band, please post it here. I'd like to see how many manufacturers did this.