HISTORY of RADIO. WGRL Kiya & Odetta 10/2014

Transcription

1 HISTORY of RADIO WGRL Kiya & Odetta 10/2014

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3 INTENSITY: the amount of energy flowing in the sound waves LOUDNESS: volume is based on the strength of the sensation received by the eardrum and sent to the brain PRINCIPLES of SOUND depend on: MEDIUM: The substance (solid, water, gas) in which sound waves move is called the medium because it is the means through which sound is transmitted. In air, the forward movement of vibrating objects pushes molecules together, causing compression. The opposite effect, known as rarefaction, is the reduction of a wave s density. AMPLITUDE: The size or height of the sound wave, which we call the amplitude, indicates the strength of the signal and determines how loud a sound will be. Greater amplitude means that more energy accompanies the movement of the wave, thereby making it louder. DISTANCE: As the distance between a person and the source of the sound increases, the I & L decreases. Because sound waves move out from their source in all directions, the energy flowing in the sound waves spreads over a greater area and decreases the farther away the sound travels.

4 M O R S E C O D E T E L E G R A P H Y

5 What is a radio wave? Radio waves are a type of electromagnetic radiation that travel faster than the speed of light, and occur in nature when made by lightning or astronomical objects. Humans have harnessed their power in order to communicate sounds over long distances. Depending on the length of the wave, different frequencies of radio can travel across the earth: LONG waves tend to cover a part of the earth consistently, while SHORT waves can reflect off the ionosphere and travel around the world. Lightning Radio Sun Radio Jupiter Radio

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7 In 1902, the Poulsen - Arc radio transmitter is invented. It is one of the first technologies used to transmit AM radio. Nikola Tesla In the early 1890s, Tesla s experiments exhibit transmission of high frequency electricity. He proposes that this could be a means of telecommunication. BIRTH of RADIO Guglielmo Marconi In 1895, Marconi builds a wireless telegraph system enabling ships to communicate with the shore while they were out of visible range. In 1901, he conducted the first successful transatlantic radio communication. In 1905, Lee De Forest s invention of the vacuum tube diode leads to the invention of the Audion oscillator (1912), which made inexpensive sound radio transmission possible and was responsible for the advent of radio broadcasting in On Christmas Eve in 1906, Reginald Fessenden transmits the first radio audio broadcast: a violin playing Silent Night. By 1912, every US ship is equipped with wireless radio. Just as radio became available to the public, America went to War and the government assumed control of all the airwaves to bolster the war effort, thereby censoring it from public use. The advent of wireless communication technology drastically affected the army and navy and forever changed the way battles were fought. In 1919, the government releases control of radio patents and the Radio Corporation of America is established. RCA brought about innovations in high power radio technology and formed the National Broadcasting Company (NBC) On November 2, 1920, station KDKA made the nations first commercial broadcast, reporting the results of election day before the newspapers were printed!

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9 INTERNET AGE: DIGITAL RADIO In 1990, amateur radio experimenters began to use computers with audio cards to process radio signals, and the first digital transmissions began to be broadcast. UNC - Chapel Hill station is the first to broadcast over the internet in In 2000, Pandora Radio is launched. By 2004, Podcasts become popular, forever changing the game. By 2003, online internet radio is valued at $49 million! Sirius Satellite Radio is founded in In the fall of 2014, WGRL launches!!!