Allen B. DuMont

DuMont was born in Brooklyn, New York City, the son of Lillian Felton (Balcom) and William Henry Beaman DuMont.[1] At the age of 10, he was stricken with polio and was quarantined at his family's Eastern Parkway apartment for nearly a year. During his quarantine, his father brought home books and magazines for the young DuMont to read while bedridden. DuMont developed an interest in science, wireless radio communication, and taught himself Morse code.

His father bought him a crystal radio receiver which he assembled, took apart, reassembled and rebuilt several times. He improved his set each time he rebuilt it and later built a transmitter, while his father obtained the landlord's permission to erect a 30-foot-high (9.1 m) transceiving antenna on the roof.

While recuperating from polio, DuMont was advised to swim to regain the use of his legs. In 1914, the family moved to Montclair, New Jersey, where there was an indoor year-round pool available at the local YMCA. He graduated from Montclair High School in 1919, and went to Rensselaer Polytechnic Institute in Troy, New York, where he was part of the Alpha chapter of the Theta Xi fraternity.

In 1915, DuMont became the youngest American to obtain a first class commercial radio operator's license at age 14. The following summer, he worked as a radio operator aboard a coastal steamer making runs from New York to Providence, Rhode Island. As the summers went by, he made his way to the Caribbean, South America and, after World War I, to Europe, where, during the summer of 1922, he was stuck in Copenhagen for months because of a dock workers' strike.

After graduating from Rensselaer in 1924, DuMont worked at the Westinghouse Lamp Company in Bloomfield, New Jersey, in charge of radio tube production. There he increased production from 500 tubes per day to an astounding 50,000 tubes per day. Management gave him a $500 bonus, a small raise, and devised the "Westinghouse Award" to recognize his accomplishments. The Westinghouse Award was later presented as a scholarship award to high school seniors showing promise in a field of science (later the Intel Science Talent Search)[2] and continues to this day as the Regeneron Science Talent Search).

By 1928, DuMont was searching for new opportunities and was wooed by Dr. Lee de Forest, a radio pioneer who developed the audion tube, the original voice amplifier for radio reception. De Forest had had a checkered career as an inventor and several failed business ventures. DuMont was hired by the de Forest Radio Telephone & Telegraph Company as vice president and production manager for radio tubes. He revamped the factory with newly designed machinery: "a high speed sealing machine, automatic grid winding and welding machine, base branding machine, basing and wire cutting machine, high-frequency bombarder and numerous tube-characteristic test sets and life racks."[3] Factory capacity was increased to 30,000 tubes per day.

When De Forest took over the mechanical television system of C. Francis Jenkins, DuMont turned his attention to television. He was involved in the first television transmissions from W2XCD in Passaic. But DuMont realized that clear images would need the development of scanning in a cathode ray tube. DuMont worked to improve television transmission and reception and implored De Forest for funds to build a long-lasting cathode ray tube for television reception. De Forest denied DuMont's request because De Forest's investors were demanding better returns. DuMont subsequently resigned at the same time that De Forest sold his radio manufacturing business to David Sarnoff at RCA.

DuMont 164 Oscillograph (1939-40), an early general purpose oscilloscope

DuMont had developed an improved version of the cathode ray tube which was both cheaper to produce and longer-lasting than the typical German tubes in use– the imported tubes had a life of 25 to 30 hours. DuMont's invention of the first long-lasting cathode ray tube made television commercially viable.[4][5] He started his own company, Allen B. DuMont Laboratories,[6] in the basement of his Upper Montclair, NJ home, building long-lasting cathode ray tubes. In 1931, he sold two tubes to two college science laboratories for $35 each.

Since DuMont was a leader in cathode ray tube (CRT) design and manufacturing, it was a natural step to use the CRT as a visual measuring instrument or oscilloscope. The production of CRT's and oscilloscopes was part of DuMont Laboratories in Upper Montclair. Needing more space he moved to a larger location in Passaic, NJ in 1934.[7] Although not the inventor of the oscilloscope, DuMont designed and mass-produced practical oscilloscopes (which he called oscillographs) for all types of laboratory, automotive/equipment servicing and manufacturing applications. By the 1940s DuMont was the leader in the oscilloscope equipment market. DuMont was one of the earliest designers of the triggered sweep oscilloscope using a gas thyratron vacuum tube (forerunner to the silicon controlled rectifier or SCR). This allowed the oscilloscope to display a visual trace at a preset input signal level. In addition the sweep (trace across the CRT screen) could be regulated by the sweep speed or sweep frequency. This design allowed the oscilloscope to provide better visual detail of the signal being studied. The trigger was a frequency synchronizing type which provided viewing stability.

The profits from the oscillographs helped DuMont invest in television design and his DuMont TV Network.[2] Unfortunately the time spent on his TV ventures cannibalized his profitable oscillograph business.[8] In 1947, a young equipment manufacturer called Tektronix produced the model 511 Time Base Trigger and Sweep Oscilloscope for $795.[9] The use of time instead of frequency to measure a sweep across the CRT was Tektronix's big selling point. Time measurements make it easier to interpret pulses and complex waveforms.[10] It has been mentioned informally that Allen DuMont saw the model 511 demonstrated at an electronics show. He tried it and was impressed, but commented to Howard Vollum and Jack Murdock, co-founders of Tektronix that it was too expensive and they would be lucky to sell any.[11] Tektronix's time base trigger and time sweep generator design would become the standard in the 1950s and into the 21st century. Tektronix would replace DuMont Oscillographs as the leading selling oscilloscope brand.[12]

When Fairchild Camera and Instrument acquired DuMont Laboratories in 1960, oscilloscopes were still being made with the DuMont name brand. Allen DuMont became Group General Manager of the DuMont Division, until his death in 1965.[2] All DuMont oscilloscopes in the late 1950s and after the Fairchild acquisition were using the time base trigger and time sweep generator method introduced by Tektronix. The DuMont line of oscilloscopes continued to be produced into the 1980s.[13]

During the early years of World War II, DuMont received special government contracts to provide large 36 inches (91 cm) wide cathode ray tubes. These tubes allowed scientists working on the Manhattan Project to study the action of accelerated electrons.

In 1932, DuMont proposed a "ship finder" device to the United States Army Signal Corps at Fort Monmouth, New Jersey, that used radio wave distortions to locate objects on a cathode ray tube screen, a type of radar. The military asked him, however, not to take out a patent because they wanted to maintain secrecy, so he is seldom mentioned among those responsible for radar.

Magic Eye tube used for tuning in a 1939 Mission Bell Model 410 radio. (green glow)

In 1932, DuMont invented the magic eye tube, or Electron Ray Tube,[14] used as a tuning accessory in radios and as a level meter in mono and stereo home reel-to-reel tape recorders. In the 1930s the manufacture of mechanical panel meters were labor-intensive and expensive. Magic eye tubes provided radio designers with a less expensive and more profitable way to add a feature usually found in higher priced equipment. The general public reception was a success as customers liked the green glow and the seemingly magical way it worked. He released details on his invention the following year.[7] He sold the patent rights to RCA for $20,000 to help fund his other projects.

DuMont produced black and white televisions in the late 1930s, 1940s and 1950s that were generally regarded as offering highest quality and durability. Many of these premium sets included a built in AM/FM radio and record player.[15]

DuMont sold his television manufacturing division to Emerson Radio in 1958, and sold the remainder of the company to Fairchild Camera in 1960. Fairchild later developed semiconductor microchips. Robert Noyce, a co-founder of Intel, originally worked for DuMont as an engineer.