- Home
- Courses
- Media Technologies
- Media Technologies: Class 11, Magic of Radio
- 1 Electromagnetic Waves
- 1.1 invisible electronic impulses similar to visible light
- 1.2 discovered by James Maxwell in the 1850–60s
- 1.3 radio waves could be harnessed
- transmission (Tx)
- reception (Rx)
- 1.4 Heinrich Hertz: first documented Tx & Rx of radio wave, 1880s
- 2 Wireless Telegraphy
- 2.1 Guglielmo Marconi
- ship-to-shore communication
- patented wireless telegraphy (1896)
- 2.2 Marconi Wireless Telegraphy Company (1897)
- British naval and commercial ships
- 2.3 American Marconi (1899)
- 2.4 wireless transmission across English Channel (1899)
- 2.5 wireless transmission across Atlantic Ocean (1901)
- 3 Wireless Telephony
- 3.1 Lee deForest
- Wireless Telephone Company (1902)
- based on the Fleming Tube (based on the electric light bulb)
- audion triode vacuum tube (1907)
- detected and amplified radio signals
- 3.2 Edward Alexanderson
- 3.3 Reginald Fesseden
- first voice transmission on Christmas Eve 1906
- 3.4 Edwin H. Armstrong
- regeneration
- amplification using deForest’s audion
- developed during World War I
- 3.5 broadcasting
- transmission of radio waves to a broad public audience
- 4 “Great Man” version of history
- 4.1 Empire of the Air
- 4.2 Characters
- Guglielmo Marconi
- Lee DeForest
- David Sarnoff
- Edwin Armstrong
- 4.3 Driven men
- 4.4 “One would succeed on his own terms”
- 5 Radio Corporation of America
- 5.1 after World War I, debates to nationalize radio
- 5.2 March 1919: General Electric bought Marconi’s American division
- 5.3 October 1919: General Electric formed RCA subdivision
- 5.4 patent pool
- General Electric (founding member)
- American Marconi (acquired 1919)
- Westinghouse (joined 1920)
- American Telephone and Telegraph (joined 1920)
- United Fruit (minor partner 1921)
- 5.5 delegated business
- AT&T: radio transmitters and radio telephony
- GE & Westinghouse: radio receivers
- 6 Early Radio Stations
- 6.1 Westinghouse
- Frank Conrad
- KDKA Pittsburgh, 1920
- WJZ Newark, New Jersey, 1921
- 6.2 RCA
- took over WJZ and WJY, 1923
- 6.3 A&T
- 6.4 General Electric