ALL ELECTRONIC TELEVISION: 1935-1945

by

R. J.. Reiman, Historian

By 1935, the key components of all-electronic television systems were of acceptable quality, but were below today's standards. In May 1935, Sarnoff announced that RCA would spend $1 million for the development of a complete TV system, and would transmit from the Empire State Building. Edwin Armstrong had to remove his FM antenna to make room for the TV equipment. The first transmissions occurred in 1935 with a 4 MHz VHF channel and a carrier frequency of 49.75 MHz. Initial tests were at 343 lines and 30 frames per second, and iconoscope pickup tubes were typically 5 to 10 inches, and the small size had the advantage of obscuring the system's low definition. Philco and CBS began demonstrations also, but CBS' efforts were sidetracked by unsuccessful attempts to develop a color system.

Television requires the scanning of the receiver to be synchronized within a fraction of one-millionth of a second to the optical image of the camera. This then requires standards, a FCC responsibility, to be sufficiently high, to achieve these results. RCA and Farnsworth who were ahead in technology called for immediate action by the FCC, while competitors Philco, Zenith, Dumont and CBS wanted delay to catch up. The FCC Chairman, James Lawrence Fly, concerned with RCA's potential monopoly over TV, opted for delay.

The problem in specifying a standard was in choosing the right compromise between picture quality and bandwidth. Increasing the number of lines improved the picture's sharpness, but also increased the bandwidth. Industry committees made recommendations on the TV standards, and on frequency allocations for TV, and the FCC held hearings on these. The FCC issued an order on March 19, 1939 for 19 channels below 300 MHz and reserved 19 more above 300 in the UHF range which had not been developed. These standards are still in use today. The FCC held back on TV standards and authorization of commercial broadcasting.

Sarnoff was impatient with the FCC's delays and made a move to force the licensing of TV broadcasts which could then bring in advertising money to pay for the high development costs. He announced that RCA would manufacture receivers to standards recommended by the industry committees, and would broadcast the opening of the New York World's Fair on April 20, 1939. Under increasing pressure, the FCC authorized limited commercial broadcasting with advertising covering only the cost of programs, not operations.

Sarnoff obtained editorial support on full licensing, and the FCC in response appointed a National Television Committee to recommend TV standards. The committee, headed by W. R. G. Baker of GE, recommended a standard of 525 scanning lines and a frame rate of 30 seconds, and in April, the FCC adopted these.

World War II created a shortage of parts and technicians, but money to develop the image orthicon, which would be used to pilot bombers in precision bombing, would advance the art. The orthicon is basically a photoemissive tube in which the signal is derived from the emission of electrons from a surface on which an optical image of the scene is formed. Further progress in TV broadcasting would await the end of the war in 1945.