“Operation Bridgeport”

Research and explorations that began many years ago and had a dramatic climax in September, 1951, when RCA and NBC summarized the results of “Operation Bridgeport” - first full-scale tests of the UHF as the right-of-way of television’s future. The television industry, meanwhile, had been kept informed about the progress of the operation, from the moment of its inception in 1949.

Until RCA engineers started looking into it, the UHF had been regarded as the Antarctic of the airwaves. Practically everybody in radio and electronics knew where it was on the map of the radio spectrum, but nobody had practical knowledge about it.

The first of a series of investigations to determine the characteristics of television transmission and reception in the UHF was initiated with small transmitters at the David Sarnoff Research Center of RCA, Princeton, N. J. Then tests were conducted with a larger transmitter atop the Empire State Building in New York, and still later with a transmitter in Washington, D. C.

These tests had a number of specific objectives. RCA wanted to find out what kind of tubes and transmitters would be needed to send out a good signal for broadcast use; it wanted to know what type of transmitting and receiving antennas would be needed; what kind of circuits would best suit home television sets; also, the extent and limitation of the service area; what power would be necessary for transmissions, and what problems there were in interference.

In the course of the Washington tests, in 1948, the conclusion was reached that the only way to get the complete answers was to build and operate America’s first ultra-high-frequency television station.

Selected for this all important test was Bridgeport, Connecticut. It was chosen for two reasons. Its population of some 350,000 resided in a fringe reception area between New York and New Haven television stations; and the hilly countryside provided an opportunity to study the effects of transmission under difficult conditions of terrain.

The site for the station and tower was on a rise of land, prophetically named “Success Hill,” situated in Stratford, about 200 feet above sea level and two miles northeast of the center of Bridgeport.

Once preliminary details had been settled, the project moved ahead rapidly. The transmitter building was completed on November 15, 1949, and a 40-foot specially designed antenna was placed atop a 210-foot tower. Station equipment was designed by RCA and was installed and operated by NBC, under the call letters of KC2XAK, on 530 megacycles.

First UHF Station on Air

This experimental station went on the air on December 30, 1949, as the first and only UHF station in this country to operate on a regular daily basis. Programs for the station come from WNBT, key NBC station in New York, via microwaves and are rebroadcast without interruption over UHF for reception in the Bridgeport area. There also is a direct pickup and rebroadcast of WNBT signals, whenever desired.

Cooperating in the tests, engineers of the RCA Victor Division designed and built 50 experimental UHF television sets and 50 converters to permit standard sets to receive both VHF and UHF broadcasts. The RCA Service Company placed these sets and converters in various homes in the test area, selected to provide a fair sampling of reception conditions.

In addition, tests of the signal strength have been obtained by NBC by use of a mobile receiving unit in a station wagon, that has moved up and down highways and parkways checking reception and measuring signal strength in practically all sections of the area. Out of this came a field-survey map of major importance.

During the Bridgeport tests, RCA and NBC engineers prepared graphs, charts and diagrams, proving the capabilities of UHF and comparing its performance with VHF. To obtain a direct comparison, NBC built and operated a small VHF transmitter, with the same antenna elevation as the UHF station, and operated the two simultaneously.

In accordance with RCA’s policy of making available research and know-how to the entire television industry, this technical knowledge was promptly passed on to other manufacturers and to the entire TV engineering profession. As a matter of record, 64 manufacturers supplemented this information with visits to Bridgeport and used the signals from the RCA-NBC station to test their own converters and UHF receivers.

Success of Operation

Leaders of the television, industry, as well as members of the FCC in Washington, who observed the operation in 1950 and 1951, generally agree that the Bridgeport field experirneni has proved, eminently successful. As Dr. C. B. Jolliffe, Vice President and Technical Directoi of RCA, who arranged and supervised “Operation Bridgeport,” declared:

“This pioneering station proves beyond a doubt that UHF television is a practical means for extending television service to communities now without it. And make no mistake, Main Street is just as anxious for television as Broadway -perhaps more so. For Broadway has its shows and its lights. But for the living present to be brought to the sitting room in a lonely farm house miles from the nearest city that is truly pushing back the horizons of entertainment and education. We feel that the Bridgeport test, conducted by RCA as a public service, points the way to a truly nation-wide television network.”

Earlier Explorations

Long before the success at Bridgeport, RCA engineers and scientists had explored waves of many frequencies and harnessed their potentialities for a wide array of useful services, including international radio communications, AM and FM broadcasting, microwave relays, radar and loran, as well as VHF television.

It was only through the opening of each new area of the spectrum and the releasing of higher and higher frequencies that these services came into being. Virtually all commercial usage of the higher frequencies can be traced directly to research, which has proceeded without interruption since formation of RCA in 1919.

To prove and understand the phenomenal characteristics of the higher frequencies that seemed to zoom from their signal source off into space, RCA engineers flew testing equipment in balloons and dirigibles at various distances and altitudes, tracing the course and direction of these waves. It was found, also, that unlike the lower frequencies, service areas of the very-high-frequency operations remain substantially constant day and night.

This research into the upper frequencies had but slight reward in its early stages, but as the crowding of the lower portion of the spectrum. increased, it became more and more important.

In 1931, RCA engineers installed the first commercial high-frequency network in the world for the Mutual Telephone Company in the Hawaiian Islands. In 1936, RCA completed a two-way microwave link for commercial operation between New York and Philadelphia.

In the course of their work, scientists and engineers of RCA have published well over a hundred technical papers on their findings in the upper frequencies. Much of this research has become basic information for the entire radio-television industry.

A great speed-up in the exploration of the higher frequencies occurred during World War II for the use of direct-line, static-free communication links, as well as radar. But it took television - and its tremendous postwar expansion as a new dimension of radio - to bring the higher frequencies to the fore and show the full importance of RCA’s continuous research.

RCA/The Story of Television RCA,1951