A Brief History of Radio Frequency

 So if we look at life in the 21st century where everything and everyone is connected and no distance is too far, how does this all happen or what is the invisible force that forms the connection between everything?

These invisible waves are better known as Radio Frequencies.

What is Radio Frequency?

Radio Frequency (RF) is the Electromagnetic waves between the range of 300kHz to 20kHz lying just between audio frequencies and infrared frequencies. The energy of an oscillating current radiates into space from a conductor hence called waves at these frequencies.

Who Discovered Radio Waves?

The field of Electronics saw a lot of discoveries in the late 1800s and the early 1900s. For example, in this same golden era in Karlsruhe, Germany a physicist named Heinrich Hertz discovered and proved the existence of radio waves. Karlsruhe Institute of Technology still exists to this day.

Up until he arrived at Karlsruhe in 1885 everything about electromagnetic waves was a theory. With two compelling but contradictory theories existing with no proof of the reality of the situation. We cannot learn about Electromagnetic waves and not know about James Maxwell. It was the Theories of this Scottish physicist that was further made scientific facts by Heinrich Hertz.

The contradiction lied regarding the speed at which these waves traveled. One theory predicted that these waves travel instantly, meaning rotating a magnet will affect all the charges in its vicinity instantly. While Maxwell argued that these waves traveled at a speed of light through space.

Hertz experiment

Heinrich Hertz was to design an experiment that could end the contradiction between the two dominating theories. The experiment consisted of an oscillator and a copper antenna. The antenna had knobs with minute spaces between them. The goal of the experiment was to determine if the sparks produced by the oscillator could reach the antenna that was placed a certain distance away(a few yards).
The small gaps were  100^th of a millimeter hence the experiment was performed in the dark and aided by a microscope.
And hence a spark produced by an oscillator did travel a few yards to a nearby antenna and Hertz could see the spark form in it.
The success of this experiment was published in 1888 as ‘Strahlen elektrischer Kraft’ or “rays of electric force” ending the contradiction and proving Maxwell was right.

Heinrich Hertz stopped his pursuit of radio waves after successfully proving Maxwell’s theory and died of an infection in 1894. It wasn’t until 1930 that the unit of frequency was named after him. This discovery changed everything in terms of communication.

Types of Radio Waves

The Use of Radio Waves In The Modern World

The primary use of Radio Waves is in different types of communication. The figure shows the estimations of the places various forms of communication hold in terms of wavelengths. The most interesting part of this spectrum is the microwaves used in communicating with satellites to give us the GPS (Global Positioning System) and in our homes in microwave ovens. The other important applications of radio waves are metal detectors and MRI (Magnetic Resonance Imaging).