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Etheric Force: Radio Waves
But the tube wasn’t Edison’s only contribution to radio. He made another important discovery. This one concerned electrical energy radiation. In working with an electromagnetic vibrator (similar in principle to the common doorbell), he found that he could draw sparks from the vibrating arm by touching it with a wire. The sparks didn’t behave like ordinary electrical sparks, though. For example they wouldn’t charge an electroscope. After much study and experimentation, Edison concluded the sparks represented a “true unknown force.” He referred to it as “etheric force.” In reality, Edison had been experimenting with what are presently known as electromagnetic or radio waves. And his etheroscope (for detecting etheric force) thus became the first detector of such waves.
Now that we know a little about Edison’s contributions to radio, let’s turn our attention to the radio itself. One of the questions that may be popping into your mind at this point is . . .
How Does a Radio Work?
Radio principles are not the easiest things in the world to understand. So here’s a very general explanation of what is happening as you listen to your crystal radio:
Suppose the weatherman is talking. The vocal sounds he makes into the microphone at the broadcasting studio are converted into electrical signals. After going through various stages of electronic hocus pocus, the treated signals are fed into the transmitting antenna. There they are radiated in all directions as waves of a frequency belonging to that station (whose frequency is different from that of any other station in your area; otherwise you’d hear all stations at once).
As the incoming waves cut across the antenna of your crystal receiver, they induce signals of that station’s frequency in the antenna. The induced signals enter the receiver, which converts them back to sounds that are almost identical to those made by the weatherman.