2. History
• In 1888 German physicist, Heinrich Hertz,
discovered radio waves. Hertz also
discovered how to transmit radio waves by
a transmitting oscillator. These waves
could be sent to space, and remotely
detected. He detected them with a small
metal loop. They were affectionately
named “Hertzian Waves”.
3. History Part II
• Guglielmo Marconi was fascinated by
Hertz discoveries. He discovered that if
you can transmit and detect radio waves
over long distances, wireless telegraphy
can be created. He experimented with this
and patented it in 1897. He received much
praise on March 3, 1899, when wireless
telegraphy was used to save its first lives.
4. History III
• In 1907 the human voice was broadcasted
for the first time instead of Morse code. In
1920 commercial radio broadcasts were
broadcasted for the first time. From then,
it has been used from everything to
information, to music, to comedy.
5. AM vs FM
• AM is the method of sending radio signals via amplitude
modulation. This means that the height of the radio wave
peaks are altered but the frequency is not. AM was the
first method to be used. Its sound quality is inferior to
that of FM transmissions but its range especially at night
is far greater than the range of FM which uses the
alternative method of frequency modulation.
6. Role/Functions
• Information
• Entertainment
• Military use
• Radio gave people in the 1930’s hope during the Depression.
• Radio can be used anywhere radio waves are present.
• Out of all types of media, the radio is most adaptable in various
physical circumstances, such as cooking and cleaning.
7. References
• The History of television:
http://library.thinkquest.org/18764/television/history.html
• Author: Wikipedia (26 January 2012)History of radio.
http://en.wikipedia.org/wiki/History_of_radio#Invention
• Author: Bev Parker, The History of Radio.
http://www.localhistory.scit.wlv.ac.uk/Museum/Engineering/Electroni
cs/history/radiohistory.htm
