Q: At first, how did people generally perceive wireless?
SD: You know, whenever anybody talks about radio, they use the word
miracle, and we see the word miracle used a lot at the turn of the century and
then again in the 20s. And to us, the word miracle has become so evacuated of
meaning. We use it to describe mayonnaise, right? So that it's hard for us to
really grasp that this was miraculous. People were used to seeing wires strung
up everywhere to transmit communication. Here, there was nothing. And people
regarded this with great awe and reverence and mystery, and it really seemed
utterly miraculous to them that somehow through the air communication could
travel.
Q: How did this mysterious technology work, in simple terms?
Wireless is based on the principle that rapid changes in electric and magnetic
forces send waves spreading through space. One way you can generate such a
rapid change is through a spark, and that's what Marconi used. He used a
device called a spark gap, and the spark gap produced high voltage alternating
current, which indeed sent waves out into space. Now, what he did was
connected this to a telegraph key, and he sought to moderate the spark gap
emissions by sending short bursts of energy--those were dots--and long bursts
of energy--those were dashes. Now, on the receiving end, you had to be able to
pick these signals up. Marconi was a wonderful technological revisionist. He
borrowed lots of different components from different inventors and put them
together in a system that worked. On the receiving end, he borrowed a device
called the coherer, which was filled with shavings of metal filings. When the
electromagnetic waves, the radio waves, hit the coherer, these filings cohered,
hence the name, and they allowed a current to pass through, and so you'd get
the signal. Then a little tiny hammer tapped the coherer, knocked the
coherence out of the filings, and so they were ready to pick up the next
incoming signal. As you could imagine, this was a rather slow and tedious
method of reception, but it did work.
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