Lesson Plan - Get It!
- Have you ever witnessed something so astonishing and so surprising that you had trouble believing your own senses?
On 24 December 1906, such an event occurred. Sailors and radio operators were at their posts waiting for the latest Morse code message when suddenly they heard something shocking!
Some thought they had just experienced a miracle; they thought they had just encountered an angel or even God himself. Others must have been baffled by what was transmitting over thier radios.
Before we reveal the astonishing details, let's consider what these radio operators were expecting.
You see, up until this point, the radio was used only for Morse code, a series of dots and dashes or short beeps and longer beeps, where the pattern of beeps represents letters and each letter and symbol has its own set of dots and dashes.
Radio operators were highly skilled - trained in how to decipher those dots and dashes into letters and then into words and sentences. They also knew how to send a message back across the waves in the same way. This was the only way to communicate across long distances.
Take a look at this Morse code sentence:
.. / .-.. --- ...- . / . .-.. . .--. .... .- -. --. --- -.-.--
- What do you think it says?
Use the Morse Code Translator from Morse Code World to find out!
Morse code was invented in the early 1800s; by 1906, it was nothing new.
When sailors heard the code for "CQ CQ CQ" at 9 pm on 24 December 1906, they knew that they should pay attention to an important message from the radio.
This by itself was not surprising. Sailors often used radios to share information about weather conditions, routes, and enemy territory. However, what followed on the call this night was not a Morse code message. It was a voice!
Now, you're probably thinking, what's the big deal? Today, we hear voices from everywhere - our televisions, our computers, our phones. Even our doorbells can talk to us!
However, in 1906, this was most definitely not the case. Although phone calls had been around for about 30 years at this point, telephones were relatively rare and could only be used to communicate from one point to another via wires, not to broadcast to many people wirelessly.
So when the sailors and other listeners heard a human voice - that of a human who was not in the same room with them - it must have been pretty freaky!
Imagine turning on your television only to have the characters step out of the TV and into your room.
- How would you feel? Excited, astonished, confused, maybe frightened?
The listeners in 1906 likely felt all these emotions and more. One thing is certain - they were witnessing something that had never occurred before.
Before we look at the message that was heard on this historic night, let's take a look at the journey that got us there and the person responsible - a Canadian named Reginald Aubrey Fessenden.
Image by Thomas H. White, via Wikimedia Commons, is in the public domain.
Early in his career, Fessenden worked as chief instrument tester for Thomas Edison. It was here that he learned about wiring and electricity. He impressed Edison and their clients with his ingenuity and intelligence.
Fessenden worked on dozens of projects, including the telegraph machine. He was able to send telegraph signals over 6,000 miles away, further than any other inventor.
In the year 1900, Fessenden made another technological advancement - he sent a vocal message wirelessly for the first time. The message only traveled about a mile and was barely intelligible, but Fessenden was excited by this success.
This test caused Fessenden to have a realization. The tool that was used to send radio waves, a spark transmitter, wasn't going to work. He needed a transmitter that would send out continuous waves rather than one that sent damped waves.
Damped waves are radio waves that are short-lived. Their amplitude, or height, decreases over time. (If you want to read more about amplitude and the parts of a sound wave, check out our lesson found under Additional Resources in the right-hand sidebar.)
We don't see sound, so it can be easy to forget that it's a real thing.
Sound travels in waves, which enter our ears and make parts of it vibrate. The speed and force of the vibrations are interpreted by our brain as sound with varying volumes and pitches.
When the frequency of a wave is changed, the sound we hear changes. Waves that are traveling at a higher frequency (faster and more bunched together) produce sounds that have higher pitches, and waves traveling at a slower frequency have a lower pitch.
(If you are interested in learning more about sound, check out our lessons under Additional Resources.)
Fessenden needed to use undamped or continuous waves. He would then be able to alter the frequency of these waves so that he could clearly transmit sounds of varying pitch such as voices or music.
This had never been done before, and his peers believed that it was impossible to send radio signals in such a way. They thought that the electrical impulse created by the spark transmitter was necessary to send radio waves and that it would not be possible to send clear audio using this same method.
After many failed attempts, Fessenden had a breakthrough. He changed an electrical alternator so that it would work much faster, generating tens of thousands Hz (hertz) instead of the usual few hundred Hz. This created a high-speed alternator that could produce continuous waves.
Image from The American Telephone Journal, via Wikimedia Commons, is in the public domain.
A small carbon microphone was then added to the antenna wire. The microphone caused the waves to be modulated (changed) to match the sound that was being sent.
When those waves were picked up by radio antennas, they could then be heard as sound waves coming through the radio.
This method of radio transmission was called amplitude modulation, known today as AM radio.
On Christmas Eve 1906, Fessenden shared his invention with the public, forever changing history.
At 9 pm, sailors across the Atlantic Ocean and in the Caribbean Sea heard this message:
-.-. --.- / -.-. --.- / -.-. --.-
The morse code reads "CQ, CQ, CQ" which means pay attention to an important message. The sailors waited, listening.
And then it happened. They heard a voice.
Reginald Fessenden himself gave a short speech. Then a song was played using Edison's phonograph machine, an early record player.
The plan was for Mr. Stein, Fessenden's assistant, to introduce Fessenden's wife and secretary who would sing and read from the Bible. However, when the time finally came, all three were struck silent by fear.
It was the first known occurrence of mic fright and was immediately followed by another first, the first instance of dead air!
Reginald was not about to let this stop his moment, though. His listeners were going to hear some live music, even if that meant he had to do it himself.
He grabbed his trusty violin and played O Holy Night. Before signing off for the evening, Fessenden read a passage from the Bible and wished his listeners a Merry Christmas.
On 24 December 1906, Reginald Fessenden did more than simply create the first radio broadcast. He made it possible for the human voice to travel distances that had never before been possible and connected us all.
Head over to the Got It? section to review what you've learned and take a closer look at Fessenden's accomplishment!