Hertz

January 9, 2021

by Paul McGowan

I can’t begin to count the number of times I’ve written the abbreviation, Hz—1 kHz, 1,000 kHz.

It is, of course, short for Hertz.

The car company?

Heinrich Rudolf Hertz was a German physicist who first proved the existence of electromagnetic waves. Invisible forces that had a specific periodicity (frequency) that later were named in his honor.

Invisible waves were first proposed by a Scottish fellow, James Clerk Maxwell (no, not the hammer murderer Maxwell Edison) who first connected the idea that three forms of energy—electrical, magnetic, and light—were all related to each other. To make it even more interesting, they all seemed to travel at the same speed (the speed of light) and they all acted in the same way (like waves). He summed these conclusions up mathematically in what later became known as Maxwell’s equations.

It was our friend Hertz (no, not the owner of Hertz Drive-Ur-Self System), who would not only prove that which no one had yet shown, that electricity and magnetism could travel through space as waves (like visible light). It was easy for people to wrap their heads around the idea of light traveling through space because we could see it. But invisible electricity or magnetism? These were spooky unseeable phenomena.

Hertz not only proved Maxwell’s Equations were correct, but in so doing, he also invented the first radio transmitter.

“Hertz’s first radio transmitter: a capacitance loaded dipole resonator consisting of a pair of one-meter copper wires with a 7.5 mm spark gap between them, ending in 30 cm zinc spheres. When an induction coil applied a high voltage between the two sides, sparks across the spark gap created standing waves of radio frequency current in the wires, which radiated radio waves. The frequency of the waves was roughly 50 MHz, about that used in modern television transmitters.”