Technology of transfering and delivering message using communication channel are disseminated (Henrich 1993) Media is extension of teacher refers to various means of communication (Sakram 1982) Radio Radio is a technology used for transmission of signals by means of modulation and electromagnetic radiation (electromagnetic waves).These waves propagate across and through the air and can also propagate through the vacuum of space, because these waves do not require a carrier medium (such as air molecules). Radio waves are a form of electromagnetic radiation, and is formed when an electrically charged object is modulated (increased frequency) at frequencies contained in the radio frequency (RF) in the electromagnetic spectrum. These radio waves are at a frequency range of 10 hertz (Hz) to several gigahertz (GHz), and electromagnetic radiation moves by way of oscillating electric and magnetic.
HISTORY OF RADIO
Tomorrow (Saturday) night, FAMH will read a story on LIVEWIRE, the venerable weekly live radio smorgasborganza and podcast, hosted by Courtenay Hameister.
The history of radio is the history of technology that produced radio equipment that uses radio waves. Initially the radio signal transmitted through either continuous wave data by amplitude modulation (AM), and frequency modulation (FM). Shipping method is called an analog signal. Furthermore, as technological developments internet, and digital signal then changes the way the transmission of radio signals. In the early 1890s an Italian named Guglielmo Maconi create innovations on the basis of equipment created by Hertz. Marconi had managed to increase the distance an electromagnetic wave emission and fill it with information. In 1895, an inventor named Guglielmo Marconi of Italy combines the theories that already exist (about electromagnetic) with his own.He was the first to transmit radio signals through the air. He uses electromagnetic waves to transmit code telegraph signal in a range of more than 1.5 Km.
E H Armstrong
Radio May 1924. Photograph of Edwin H. Armstrong with a prototype of the RCA second harmonic superheterodyne.
In 1918, Edwin H Armstrong of Columbia University developed a radio receiver, which is called the Super heterodyne circuit. In 1933 Armstrong introduced FM radio system (frequency modulation), which gives crystal clear reception even though there was a storm and offers high sound accuracy that previously lacked. Over the clarity of the resulting sound in the early ’60s, dominating the FM channel radio system, and even used for communications between Earth and outer space by the U.S. National Space Agency, NASA. History of using radio a. Radio AM Radio AM (amplitude modulation) works with the principle of radio waves and waves modulate audio. Both are equally have a constant amplitude. But this process then converts the amplitude modulation wave conductor (radio) in accordance with the amplitude of the audio waveform.
a. Radio FM Radio FM (frequency modulation) works on a similar principle to the AM radio, by modulating radio waves (conductors) with an audio waveform. However, the FM modulation process is causing the change in frequency.
b. Internet Radio The discovery of the Internet began to change the transmission of analog signals used by conventional radio. Internet radio (also known as web radio, streaming radio and e-radio) works by transmitting sound waves through the internet.