The company known today as Zenith was founded at a kitchen table in Chicago in 1918 by Karl Hassel and Ralph H. G. Mathews. In 1919, Hassel and Mathews moved their operations into a 14-by-18-foot garage, where they formed the Chicago Radio Laboratory (CRL). They used half of the garage to make hand-engraved radios out of Bakelite and the other half for their amateur radio station, 9ZN.

That same year, the Chicago Radio Laboratory began placing advertisements for its products in “QST,” the American Radio Relay League’s Magazine. One of CRL’s employees suggested that 9ZN be listed with a small “ith” after it. 9ZNith soon became Z-Nith.

In 1921, CRL moved into a 3,000-square-foot factory in Chicago. In early 1922, the company was making five radios each week; by June of that year, it was making 50 per week. With investment money from Eugene F. McDonald, Jr., Hassel and Mathews founded the Zenith Radio Corporation in 1923 as a marketing division for CRL. A few years later, the two merged and both manufactured and advertised under the Zenith name.

Zenith quickly became known as an innovator. It released the first portable radio in 1924, followed two years later by the first radio that operated entirely on household electricity. In 1927, Zenith introduced the first radio with push-button tuning, and in 1940 it broadcast the first FM radio station in the Midwest. In fact, Zenith co-invented the FM stereo broadcast system, which was authorized by the FCC in 1961.

Zenith expanded throughout the 1920s. In 1927, the company debuted its now-famous slogan, “The Quality Goes in before the Name Goes On.” The company also helped found the Consumer Electronics Association, and Zenith’s CEO was the first president of the National Association of Broadcasters.

With the coming of the Depression, Zenith was forced to change its focus from high-quality radios to more affordable ones. Following the lead of Philco’s Baby Grand, Zenith released its own cathedral radio, the moderately successful Zenette Model L, in 1931. Like many of Zenith’s other radios of that era, the Zenette featured an Art Deco design.

Zenith also produced chairside and table models, many of which had a handle on top to make them even more portable. The company’s 500H was considered the highest-quality portable...

During World War II, Zenith made bomb fuses and other devices for the government. Afterward, the company shifted gears and devoted most of its attention to televisions. Here, too, Zenith became an innovator, releasing the first wireless remotes for TV in 1955 (the Flash-Matic) and 1956 (the Space Command).

Collectors of Zenith radios can use model numbers to help identify a radio’s model year. From 1930 to 1935, each radio had a two- or three-digit model number; in general, larger number models were made later in this five-year stretch.

Starting in 1936, Zenith’s radios had a much more descriptive six-digit model number. The 6-S-646 is a good example of the typical format. The first 6 indicates the type of vacuum tubes in the unit (this figure could be one or two digits). The S indicates the capabilities of the model; D, for example, meant the model had AC/DC power and only received the broadcast band, whereas S usually meant that the radio was AC-powered and also received one shortwave band.

The first number of the last three digits indicates the model year. The number 1 corresponded to 1937 model radios, 2 corresponded to 1938, and so on (if this number was missing, that indicated a 1936 model year). Finally, the last two digits indicated how deluxe the model was, with lower number models generally having fewer features than models with higher numbers.

In 1950, Zenith switched to a four-digit model-number system. The first letter indicated the model year, with G corresponding to 1950, H corresponding to 1951, and so on. The three digits afterward were somewhat arbitrary.

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