Early television technology frequently asked questions

The television picture is created on the surface of the cathode ray tube (CRT)As we look at the history of television, I wanted to tackle some of the frequently asked questions about the origins of the technology, as well as share some cool resources on movies and television.

One commonly asked question is why the early televisions had round screens. The television picture tube was a vacuum tube that contains one or more electron guns and a phosphorescent screen used to display images known as a cathode ray tubes (CRT).  When the original cathode ray tube was invented it was an experimental device, television was not yet developed. The natural shape of the cathode ray tube was round, as shown here in the diagram. The cheapest and easiest way to manufacture a CRT was to make it round.

The television picture is created on the surface of the cathode ray tube by drawing it rapidly line by line. The entire front area of the CRT is scanned repetitively and systematically in a fixed pattern. Before 1940 there was no standard in the United States for how the picture was created electronically using the cathode ray tube.

In 1940 the Federal Communications Commission (FCC) established The National Television System Committee (NTSC) to resolve the conflicts that were made between companies over the introduction of a nation wide analog television system in the United States.  The NTSC standard selected 525 scan lines, an aspect ratio of 4:3, and frequency modulation (FM) for the sound signal. The number of 525 lines was chosen as a because of the limitations of the vacuum-tube-based technologies of the day.

The Lost and Forgotten DuMont Television Network

The Lost and Forgotten DuMont Television Network


There is a lot of entertainment and television broadcasting history found in the often lost and forgotten fourth television network created by scientist and inventor Allen B. DuMont.

DuMont was an American electronics engineer, scientist and inventor best known for improvements to the cathode ray tube for use in television receivers.  DuMont Laboratories was the primary manufacturer of cathode-ray tubes in the United States in the 1930s and was fairly successful in the manufacturing of TV receivers.

To sell televisions, DuMont started the DuMont Television Network in 1946.  The television broadcasting division of DuMont separated from the manufacturing division in 1955. The DuMont Television Network ceased operations in 1956. The DuMont consumer products manufacturing division would be purchased by Emerson Electric Company in 1958.

The DuMont Television Network had a difficult time competing for big name stars and talent of the day. The big three networks were all spin offs from radio networks which provided financial support for their television divisions. Some folks attribute the failure of the DuMont Television Network on the lack of backing from a radio network.

Growing up, like many baby boomers in the United States, I remember the big three television networks in the 1960s were NBC, ABC, and CBS. Any reference to a fourth network might make me think of PBS.

When making the statement the forgotten fourth network, some people may think that is meant to be a joke about the current fourth television network the Fox Broadcasting Company, rather than a reference to the DuMont Television Network, a functional on the air television network from 1946 to 1956.

Who invented Television Philo Farnsworth versus Sarnoff and Zworykin

Vladimir Zworykin and RCA Chairman David Sarnoff recount early researchThe invention of television was the work of many inventors over several decades, as we discussed in our previous article. Turning the vision of the television as an invention into a real commercial product that occupied American homes was the work of business visionary David Sarnoff with the help of Russian American scientist Vladimir Zworykin.

Scientist and inventor Vladimir Zworykin

As a young engineering student, Vladimir Zworykin worked for Russian scientist and inventor Boris Rosing and assisted him in some of his laboratory work at the St. Petersburg Institute of Technology in Russia. Following the Russian Revolution, Zworykin moved to the United States in 1919. Zworykin found work with Westinghouse Electric Corporation in Pittsburgh. Based on their pioneering efforts in radio, he tried to convince them to do research in television. His work on television resulted in two patent applications. The first, entitled "Television Systems" was filed on December 29, 1923, and was followed by a second application in 1925 that was awarded in 1928.

Zworykin applied to the physics department at the University of Pittsburgh in 1924. Due to his previous credited work Zworykin received his Ph.D. only two years later upon completion of his dissertation on the improvement of photoelectric cells.

Zworykin demonstrated his invention for television to Westinghouse executives in 1925. According to Zworykin himself his demonstration, was “scarcely impressive.” The Westinghouse executives suggested that Zworykin should spend his time on more practical endeavors.

Business visionary David Sarnoff

In 1917, General Electric purchased the American branch of the Marconi Company and combined its radio patents to form a new company called the Radio Corporation of America (RCA). Russian born David Sarnoff was promoted to General Manager of RCA in 1921 and was given full authority to run the company. In the 1920s David Sarnoff of RCA had the vision of developing television.


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