United States

KDKA Pittsburgh Celebrates a Century of Broadcasting.
KDKA Pittsburgh [nowaday 1020 kHz] began regular broadcasting 100 years ago today when the station began an election night broadcast at 6 p.m. on Tuesday, Nov. 2, 1920, from a tiny shack atop one of the Westinghouse Electric buildings in East Pittsburgh.
Four men manned that first broadcast: Engineer William Thomas; telephone line operator John Frazier; R.S. McClelland, a standby; and Leo Rosenberg, radio’s first announcer.
The election returns of the Harding-Cox presidential race were relayed to about 1,000 listeners who learned through this incredible new medium who the next president of the United States would be. (Spoiler Alert: Warren Harding beat James Cox.)
Steve Millam in MWDX – The National Radio Club fb group (2020-11-02)

United States

KDKA Centennial -The birth of Commercial Radio.
November 2, 2020 marks the centennial of radio station KDKA going on the air for the first time. Their first broadcast, considered by many to be the birth of commercial broadcast radio, was to report the election results of the Harding-Cox presidential race. KDKA has been on the air continuously ever since.
To celebrate this historic milestone, Pittsburgh area amateur radio operators, also known as hams, will take to the airwaves with a series of special event stations. Their goal is to contact as many other ham radio operators across the United States and around the world. They will be celebrating the centennial of KDKA for the entire month of November.
KDKA originally began operations in 1916 as an amateur radio station, call sign 8XK, operated by Dr. Frank Conrad, Assistant Chief Engineer of Westinghouse Electric and Manufacturing Company. During World War I, amateur radio operations were ordered to be suspended because of national security concerns. After the war, the operators reorganized the station as a commercial AM radio station. The first transmissions of KDKA were from a makeshift studio on a roof of the Westinghouse K Building in East Pittsburgh.
http://www.southgatearc.org/news/2020/october/kdka-centennial-the-birth-of-commercial-radio.htm#.X5V0voj0mM8
Southgate Amateur Radio News (2020-10-25)

United States

Radio Broadcasting became a reality: Nov. 2, 1920.
By the end of the 20th century’s second decade, three key elements were in place to fuel radio broadcasting: resonant circuitry, a practical means for generating a carrier wave, and methodology for impressing speech and music on that carrier.
These waited only for someone to combine them in an effective way.
A number of individuals — most notably Reginald Fessenden, Lee de Forest and Charles Herrold — had made varying attempts at broadcasting. None took root.
There was little effort to stimulate interest among the public. Early transmissions of speech and music were directed to radio amateurs. There also was little or no notification of how to “listen in.” Nor were there regular operating schedules, nor readily available receivers for the general public. Radio sets were marketed to commercial enterprises, the military and radio amateurs.
[….]
This stemmed from the government’s decision not to allow foreign corporations such as Marconi to exert a virtual monopoly in this area of radio, as had been the case before the war. While that chapter in radio history is too involved to relate in detail here, it resulted in the creation of the Radio Corporation of America.
RCA, along with General Electric, a large player in radio communications, wound up controlling most of the valuable radio patents.
Westinghouse attempted to enter into international radio communications, joining with the International Radio Telegraph Co., successor to Reginald Fessenden’s National Electric Signaling Company, in an attempt to secure a place in this field. The initiative failed due to postwar agreements in place by others including Marconi, Telefunken, and RCA, the new kid on the block.
[….]
Radio World NewsBytes (2020-10-07)