Working With Marconi
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these sent out trains of electric waves through the ether.
By holding his resonator, or as we would call it now, his detector, at a little distance from his sending apparatus, when the latter sent out the electric waves they would set up electric
oscillations, or currents of high frequency, in the ring detector and ‘these in turn would make a stream of little sparks jump across the gap between the balls.
Here, then, was a complete wireless sending and receiving apparatus, but it would work only a short distance, probably not over 100 feet. But Hertz was not trying to invent a wireless telegraph; all he wanted to and did do was to prove that there were long electric waves and there his work ended.