THE RADIO AMATEUR'S HAND BOOK
| Photograph unavailable |
| A. Frederick Collins, Inventor of the WirelessTelephone, 1899. Awarded Gold Medal for same, Alaska Yukon PacificExposition, 1909. |
A Complete, Authentic and Informative Work onWireless Telegraphy and Telephony
BY
FREDERICK COLLINS
Inventor of the Wireless Telephone 1899; Historianof Wireless 1901-1910; Author of "Wireless Telegraphy" 1905
1922
TO
WILLIAM MARCONI
INVENTOR OF THE WIRELESS TELEGRAPH
Before delving into the mysteries of receiving and sending messageswithout wires, a word as to the history of the art and its present dayapplications may be of service. While popular interest in the subjecthas gone forward by leaps and bounds within the last two or threeyears, it has been a matter of scientific experiment for more than aquarter of a century.
The wireless telegraph was invented by William Marconi, at Bologna,Italy, in 1896, and in his first experiments he sent dot and dashsignals to a distance of 200 or 300 feet. The wireless telephone wasinvented by the author of this book at Narberth, Penn., in 1899, andin his first experiments the human voice was transmitted to a distanceof three blocks.
The first vital experiments that led up to the invention of thewireless telegraph were made by Heinrich Hertz, of Germany, in 1888when he showed that the spark of an induction coil set up electricoscillations in an open circuit, and that the energy of these waveswas, in turn, sent out in the form of electric waves. He also showedhow they could be received at a distance by means of a ring detector,which he called a resonator.
In 1890, Edward Branly, of France, showed that metal filings in atube cohered when electric waves acted on them, and this device hetermed a radio conductor; this was improved upon by Sir OliverLodge, who called it a coherer. In 1895, Alexander Popoff, of Russia,constructed a receiving set for the study of atmospheric electricity,and this arrangement was the earliest on record of the use of adetector connected with an aerial and the earth.
Marconi was the first to connect an aerial to one side of a sparkgap and a ground to the other side of it. He used an induction coil toenergize the spark gap, and a telegraph key in the primary circuit tobreak up the current into signals. Adding a Morse register, whichprinted the dot and dash messages on a tape, to the Popoff receptor heproduced the first system for sending and receiving wireless telegraphmessages.
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| Collins' Wireless Telephone Exhibited at theMadison Square Garden, October 1908. |
After Marconi had shown the world how to telegraph withoutconnecting wires it would seem, on first thought, to be an easy matterto telephone without wires, but not so, for the electric spark sets updamped and periodic oscillations and these cannot be used fortransmitting speech. Instead, the oscillations must be of constantamplitude and continuous. That a direct current