Live - From Coast to Coast!
AT&T Builds Television's Version of America's Transcontinental Railroad
By Richard Wirth | September 29, 2013
Today, we think nothing of clicking our remote and have live images from somewhere else in the world appear on the screen. Push a few buttons on our computer and loved ones living far away appear. But in television's early days, a live program meant we were watching a local program.
Every station that went on the air was an island relying on couriers and the mail for any program not made by the station itself. Within a few years, however, the gestation of TV’s transmission system for the American continent developed in little geographic pieces like a jigsaw puzzle. Because video signals use so much more bandwidth than audio, the existing telephone network was not sufficient to handle the load. A whole new infrastructure was needed.
Most Americans watched shows produced live for New York weeks later when their local station received a “kinescope” of the show. With videotape still years away, the only way to record a show was to point a motion picture camera at a video screen, process the negative, make prints and ship them to their affiliates across the country.
We hear the term Broadband used to describe our home Internet and/or cable service. Before 1936, telephone lines were on twisted copper wire. Then the American Telephone and Telegraph Company (AT&T) began experimenting with an 1880 invention by Oliver Heaviside - Coaxial cable. Coax, as it is nicknamed, is the first form of broadband. Heaviside was a self-taught British electrical engineer who later became best known for the layer in the ionosphere named after him that influences radio waves to "skip" and respond to the curvature of the earth.
Oliver Heaviside - Inventor of Coaxial Cable
AT&T Scientists Lloyd Espenschied and Herman Affel later applied for a U.S. patent as they improved on Heaviside's work. Back then, AT&T was part of the Bell Telephone System of regional telephone companies (Bell of Pennsylvania, Pacific Bell, Southern Bell, etc). For many years AT&T had a virtual monopoly on telephone service (and later, radio and television distribution) in the U.S. until in 1982, the courts decreed its breakup as new technologies arrived on the scene.
In addition to providing telephone service to the highest percentage of homes in the U.S., the Bell System also maintained a manufacturing operation (Western Electric), research and development arm (Bell Laboratories) and AT&T Long Lines. Long lines provided the glue that enabled the regional systems to interoperate. In 1949, if you placed a long distance call from Los Angeles to Pittsburgh, Pacific Bell transferred the call (by hand, through a telephone operator inserting a plug into a jack) to AT&T’s long lines network that then handed it back to Bell of Pennsylvania to complete the call.
Because of their common carrier status and the infrastructure they had in place, AT&T handled all radio transmission lines, including those of the major radio networks throughout the nation.
As the nation grew, orders for telephone service innundated the phone companies and, with the additional specter of television on the horizon, AT&T had to invent a way to multiplex calls to satisfy the increasing demand. Thus, the coaxial cable, the first broadband transmission medium was born. That first experimental path of coax in 1936 was installed between New York and Philadelphia. The technology of the time could only carry 480 telephone calls or one television signal.
Coaxial cable used for muliplexing telephone calls or carrying multiple television signals, 1946.
Concurrent with the development of coax was microwave relay. Microwave was developed in the military during World War II. With the war over, use of the technology for civilian purposes became possible. Limited by the curvature of the earth, a “line of sight” system of repeater towers spaced 25-30 miles apart was designed so telephone and television signals could travel from city to city. The first of these was established in 1947 with a successful connection between New York and Boston via seven towers on seven hilltops.
In late 1947, using combinations of coax and microwave, “Telco” or “Ma Bell” (as engineers referred to it) began building a transcontinental system to accommodate both telephone and television.
By 1948, some geographic areas such as the east (New York, Boston, Philadelphia and Washington), the Midwest (Chicago, Detroit, Milwaukee, Toledo, St. Louis, Buffalo and Cleveland) and the west (Los Angeles and San Francisco) were regionally interconnected.
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