The Kadette Tunemaster is simple in design. It utilizes the principle of the Superheterodyne radio circuit. After the set tunes in a desired station, it converts it to an I.F. frequency of 1570kc (A 1550kc I.F. was also manufactured for areas with a broadcast station at that frequency). At this point, rather than extracting the program signal, the I.F. frequency was simply used as a broadcast signal capable of being tuned by any standard radio.

This meant, of course, that your radio had to be tuned to 1570kc and the volume had to be at a sufficient level to allow the Tunemaster controls to function adequately.

The scheme was successful for a number of reasons. Radios could tune to 1600kc (or even 1700kc, the "expanded" AM band where police calls were often located). Broadcast stations were, for the most part, confined to the lower portion of the band, with stations above 1500kc just starting to appear, and even in areas with the newer stations, there would not have been stations assigned to both 1550kc and 1570kc.

The Tunemaster sold for $25, about a weeks pay for the average worker, and would have been a rather expensive item. The company was selling "10-tube" radios at the time for $19.95 (see: International Radio Corporation). The set was designed in the fall of 1938 for sale in 1939, and in 1939 International Radio sold the Kadette radio business. The new Kadette company lasted only a couple of years, so the number of these sets manufactured may have been rather low.

International Radio Corporation
Builders of Kadette radios (and Argus cameras), International Radio was an small but innovative company in the 1930s.

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