National Broadcasting Co.
NBC Radio Network
1935 and 1937
RED, BLUE AND ORANGE NETWORKS
In 1935, all of NBC's phone company West Coast broadcast lines originated and
terminated in San Francisco. This made San Francisco the originating point for
broadcasts fed up and down the West Coast, as well as national programs fed
eastward. But programs fed eastward required the complex process of "line
reversal" where all program amplifiers on the long route to Denver reversed
their direction simultaneously. This limited the quantity of West Coast programs
that were heard nationally. (The NBC "Orange" Network lines are drawn in
RED, BLUE AND SUPPLEMENTARY NETWORKS
Everything changed just two years later with the installation of a second
broadcast line to Los Angeles. This allowed the origination of national network
programs from Hollywood, and more nationally-known film stars were being heard
on the radio. It also eliminated the need for "line reversal", as programs were
fed westward on the San Francisco line and eastward on the Los Angeles line.
This new telephone line started the great exodus of programs and talent from San
Francisco to Hollywood. By 1942 only a handful of programming staff remained in
the City by the Bay.