Radio Waves — From Spark to WiFi (Part 2)

The person who took the next step was a young Italian named Guglielmo Marconi, barely 20 years old.

At that time, sending a message over a distance already existed.

It was the telegraph.

But it had a hard limit.

It needed a physical wire.

A cable ran from one place to the next over land and the message could only travel where the wire went.

Marconi saw that these invisible waves could do something the telegraph never could.

Carry a message through the open air with no wires at all.

But how do you actually send a message on a wave and catch it on the other end? First, how do you make the wave? Think back to part one.

You take an electric charge and you shake it very fast.

that shaking throws off an electromagnetic wave racing outward at the speed of light.

And a spark is one of the easiest way to shake a charge like that.

So Marconi used a simple switch, a telegraph key.

Press it, a spark fires and a radio wave rushes out into the air, the very same kind holds made.

Let go and the wave stops.

Press wave on, release wave off.

And to catch it at the other end, he built an antenna.

A wire raised into the air waiting for the wave to arrive.

Now, on and off by itself doesn't mean anything.

You need a code.

And one already existed from the telegraph.

Morse code.

In Morse code, every letter is a pattern of short and long signals.

A short tap is a dot.

A longer tap is a dash.