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.

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