Inventions; Science; Technology -- Social aspects; Technology and civilization
There are various systems of wireless telegraphy for the most part
called after the scientists who developed or perfected them. Probably
the foremost as well as the best known is that which bears the name
of Marconi. A popular fallacy makes Marconi the discoverer of the
wireless method. Marconi was the first to put the system on a commercial
footing or business basis and to lead the way for its coming to the
front as a mighty factor in modern progress. Of course, also, the honor
of several useful inventions and additions to wireless apparatus must
be given him. He started experimenting as far back as 1895 when but
a mere boy. In the beginning he employed the induction coil, Morse
telegraph key, batteries, and vertical wire for the transmission of
signals, and for their reception the usual filings coherer of nickel
with a very small percentage of silver, a telegraph relay, batteries
and a vertical wire. In the Marconi system of the present time there
are many forms of coherers, also the magnetic detector and other
variations of the original apparatus. Other systems more or less
prominent are the Lodge-Muirhead of England, Braun-Siemens of Germany
and those of DeForest and Fessenden of America. The electrolytic
detector with the paste between the tin blocks belongs to the system
of DeForest. Besides these the names of Popoff, Jackson, Armstrong,
Orling, Lepel, and Poulsen stand high in the wireless world.
A serious drawback to the operations of wireless lies in the fact that
the stations are liable to get mixed up and some one intercept the
messages intended for another, but this is being overcome by the
adoption of a special system of wave lengths for the different wireless
stations and by the use of improved apparatus.
In the early days it was quite a common occurrence for the receivers
of one system to reply to the transmitters of a rival system. There
was an all-round mix-up and consequently the efficiency of wireless
for practical purposes was for a good while looked upon with more or
less suspicion. But as knowledge of wave motions developed and the
laws of governing them were better understood, the receiver was "tuned"
to respond to the transmitter, that is, the transmitter was made to
set up a definite rate of vibrations in the ether and the receiver
made to respond to this rate, just like two tuning forks sounding the
same note.
In order to set up as energetic electric waves as possible many methods
have been devised at the transmitting stations. In some methods a wire
is attached to one of the two metal spheres between which the electric
charge takes place and is carried up into the air for a great height,
while to the second sphere another wire is connected and which leads
into the earth. Another method is to support a regular network of wires
from strong steel towers built to a height of two hundred feet or more.
Public-domain text, read in full here on John Shaqi.
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