The company was co-founded by Ralph Matthews and Karl Hassel in Chicago, Illinois as Chicago Radio Labs in 1918 as a small producer of amateur radio equipment. The name "Zenith" came from its founders' call sign, 9ZN. They were joined in 1921 by LCDR Eugene F. McDonald, and Zenith Radio Company was formally incorporated in 1923. Zenith introduced the first portable radio in 1924, the first mass-produced AC radio in 1926, and push-button tuning in 1927. It added automobile radios in the 1930s, with its Model 460 (bragging it needed no separate generator or battery) selling at $ 59.95. The first Zenith TV set would appear in 1939, with its first commercial sets in 1948. The company would eventually go on to invent such things as the wireless remote control, FM multiplex stereo, high-contrast and flat-face picture tubes, and the MTS stereo system used on analog television broadcasts in the US and Canada (as opposed to the BBC-developed NICAM digital stereo sound system for analogue TV broadcasts, used in many places around the world.) Zenith was also one of the first companies to introduce a digital HDTV system implementation, parts of which were included in the ATSC standard starting with the 1993 Grand Alliance.