History of Radio

Transcript

1. History of Radio History of Mass Communication
2. Important Inventions   Electric dot and dash telegraph   Telephone   Wireless telegraph   Radio telephone   Radio for mass use   1844   1876   1896   1906   Early 1920s
3. Morse Code Samuel Morse. 1844   Constructed a telegraph machine and devised a code for each letter by using long and short pulses of electricity.   He was able to attach a pencil to the piece of metal that his electromagnet attached so as to leave a record of the transmission on a moving strip of paper.
4. Morse Code Samuel Morse. 1844   Obtained grant from US Government   Strung copper wire on poles between Baltimore, Maryland & Washington over 40 miles   From Baltimore in 1844 he sent the message “what Hath God wrought?”
5. Samuel Morse
6. Telegraph Office of London Post Office
7. Transmitter/Receiver Heinrich Hertz. 1887   German Scientist constructed a simple transmitter and receiver for radio waves
8. Wireless Telegraph Gugliemo Marconi. 1895   Synthesized Heinrich Hertz’s discoveries of electromagnetic waves that travelled instantaneously without wires and the concept of transmitting messages encoded in dots and dashes via the electric telegraph   American Marconi Company in 1899
9. Radiotelephone Reginald Fessenden. 1906   Christmas eve 1906, radio operators along the Atlantic sea heard a voice reading from a Bible & record & violin playing   Previously only heard dots and dashes
10. Radiotelephone Reginald Fessenden. 1906
13. Audion Lee De Forest. 1906   Audion: 3 element vaccuum tube whaich made more sophisticated circuits and application to amplify signals   Permitted the development of small receivers   Radio transmitters and receivers about the size of a bread box played important roles in WW1   By 1918, pilots could transmit and receive from an airline to the ground
14. Mass Radio   Maritime, Commercial and Government Use to Mass Medium   Small enough for home use   Affordable   Regularly scheduled programs   Clear reception   Means of paying for broadcast
15. David Sarnoff   Proposed to American Marconi Company to broadcast music, sports scores, lectures, weather reports, concerts   Manager, Radio Corporation of America in 1919
16. Radio Programming   Dr. Frank Comrad was developing transmitting systems for Westinghouse Corporation.   He needed to test the equipment after hours, so he built a transmitter over his garage at home.   Broadcast 2 evenings a week. People sent him postcards and called requesting Victrola records
17. First Commercial Radio Station KDKA, 1920   Broadcast of the Harding Cox presidential election   A running account of the returns was phoned in from a newspaper office and read over the air. In between announcements and Banjo music was palyed
18. Staff of KDKA
19. Radio Act 1912   Original bill initiated during investigations re. sinking Titanic   US Federal law that mandated that all radio stations in the US be licensed by the federal government   Seagoing vessels continuously monitor distress frequencies   Did not prescribe frequencies
20. Radio Act 1927   Government to regulate airwaves in the interest of the people   Established the Federal Radio Commission   Broadcasting only on assigned frequencies, specified power levels and scheduled times   Replaced by Federal Communications Act of 1934
21. Mass Use   By 1922 half million sets were in use   By 1925 escalated to five million sets   By the end of the decade, 14 million radio receivers were in American homes
22. Frequency Modulation Edwin Armstrong. 1933   Developed and patented a new radio signal   It was static free   Carried higher and lower audio frequencies than amplified modulation (AM)   Ideal carrier for music   Court battle with RCA re. using the system for TV broadcast   Committed suicide before the settlement
23. Discussion   Radio in the Great Depression. 1930s   Radio in WW ll. 1939 to 1945