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Sunday, July 06, 2025 |
Radio basics
Radio is the technology of communication or exchanging information using radio waves.
Radio waves are electromagnetic waves that transmit at a certain frequency of the electromagnetic spectrum: between 3Hz and 300GHz.
This makes them the lowest in frequency and the longest in wavelength.
Radiowaves are generated by an electronic device called a transmitter, which is connected to an antenna which radiates the waves out into space.
These waves can be detected by another antenna connected to a radio receiver.
Information is transmitted by adding information to the raw electromagnetic wave. The wave by itself doesn not contain any information.
The wave form used is a sine wave that fluctuates smoothly and consistently.
There are two main methods of adding information to the waveform: AM and FM.
AM stands for amplitude modulation. Here, the amplitude of the wave is altered. The amplitude is the distance from peak to peak. For example, the sine wave produced by a person's voice is overlaid onto the transmitter's sine wave to vary its amplitude.
FM stands for frequency modulation. Here, the frequency of the wave is altered. The frequency is the number of oscillations over a given time period which we measure in Hertz.