Radio WavesPeter Hutchinson - P11255368TECH1002 – Studies in Media Technology
What are Radio Waves?• They are a type of electromagnetic radiation.• Aside from power cables, they have the longest wavelengths of any other waves on the electromagnetic spectrum and their frequency ranges from 300GHz to 3kHz.• They are used for radio communication, broadcasting, radar, computer networks, cellular communications and much, much more.
The Importance of Radio Waves• Radio waves provide the best way to globally and locally communicate information.• Almost everything that sends and receives information uses radio waves.• Without it, the world would be a much darker place.
The Birth of Radio• It is often disputed who actually invented radio communication.• Joseph Henry and James Clerk Maxwell theorised electromagnetism and the existence of radio waves, which led to the further invention of the radio.• However, in 1879, David E. Hughes discovered that sparks would generate a radio signal.• Eventually, he demonstrated the ability to send and received Morse code signals to a range of about 460m.
Early Radio Development• There were 8 early developers of the radio, most notably Heinrich Hertz and Nikola Tesla.• Hertz essentially introduced the use of antennas, which was just an unpowered spark-gap acting as a receiver. He was also able to control the frequencies of the waves, but towards the end of his life he did not seem interested in the progress he had made towards the radio.• Tesla invented the “Tesla Oscillator” which was his version of the radio, and he was able to communicate over large distances by grounding one half of this oscillator and connecting the other to an insulated surface.
Early Uses• The first uses of radio were maritime for sending telegraphic messages using Morse code between ships and land in the early 1900s.• It grew in popularity during World War I for communication between armies and navies.• Broadcasting began in California in 1909 and became feasible in the 1920s with the widespread introduction of radio receivers.
Today’s Uses• Audio – Systems such as FM and AM radio• Telephony – Mobile phones transmit to a cell site and then to a public telephone network to send and receive data• Navigation – A receiver listens to four satellites, which helps to operate our satellite navigation systems.• Radar – Radio Detection and Ranging detects objects at a long distance by bouncing radio waves off them.
Today’s Uses• Digital Radio – The earliest form of which was the spark gap telegraphy, which was used by Marconi.• Heating – Microwaves are used to heat food.• Radio Control – Remote controls use radio waves to transmit control data to a remote object. Tesla successfully a radio-controlled boat in 1898.
Conclusion• Radio waves are key to the modernisation of communication.• We rely on them for a very large percentage of our wireless controls.• There is nothing that could effectively replace them as an efficient way to transmit data wirelessly.