* I thought this was interesting… I love telephone and radio history stuff. I was browsing through a CD I had burned, downloaded from Project Gutenberg http://www.gutenberg.org/wiki/Main_Page. The etext is The Radio Amateur’s Hand Book, by A. Frederick Collins.
Another interesting site I found while reading a bit of this Radio Amatuers Hand Book, is:
http://www.ericssonhistory.com/templates/Ericsson/StartPage.aspx?id=2049&epslanguage=EN (The history of Ericsson). By now you may have guessed that this is interesting to me especially (besides being a U.S. Radio Amateur, and having an interest in Radio and Telephone Communications in general…) is because I sell and support the Ericsson W25 and W35 Cellular Voice and Internet Mobile Broadband Router line of equipment.
THE RADIO AMATEUR’S HAND BOOK
A Complete, Authentic and Informative Work on Wireless Telegraphy and Telephony
Inventor of the Wireless Telephone 1899; Historian of Wireless 1901-1910; Author of “Wireless Telegraphy” 1905
INVENTOR OF THE WIRELESS TELEGRAPH
Before delving into the mysteries of receiving and sending messages without wires, a word as to the history of the art and its present day applications may be of service. While popular interest in the subject has gone forward by leaps and bounds within the last two or three years, it has been a matter of scientific experiment for more than a quarter 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 dash signals to a distance of 200 or 300 feet. The wireless telephone was invented by the author of this book at Narberth, Penn., in 1899, and in his first experiments the human voice was transmitted to a distance of three blocks.
The first vital experiments that led up to the invention of the wireless telegraph were made by Heinrich Hertz, of Germany, in 1888 when he showed that the spark of an induction coil set up electric oscillations in an open circuit, and that the energy of these waves was, in turn, sent out in the form of electric waves. He also showed how 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 a tube cohered when electric waves acted on them, and this device he termed a radio conductor; this was improved upon by Sir Oliver Lodge, 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 a detector connected with an aerial and the earth.
Marconi was the first to connect an aerial to one side of a spark gap and a ground to the other side of it. He used an induction coil to energize the spark gap, and a telegraph key in the primary circuit to break up the current into signals. Adding a Morse register, which printed the dot and dash messages on a tape, to the Popoff receptor he produced the first system for sending and receiving wireless telegraph messages.
Collins’ Wireless Telephone Exhibited at the Madison Square Garden, October 1908.
After Marconi had shown the world how to telegraph without connecting wires it would seem, on first thought, to be an easy matter to telephone without wires, but not so, for the electric spark sets up damped and periodic oscillations and these cannot be used for transmitting speech. Instead, the oscillations must be of constant amplitude and continuous. That a direct current arc light transforms a part of its energy into electric oscillations was shown by Firth and Rogers, of England, in 1893.
The author was the first to connect an arc lamp with an aerial and a ground, and to use a microphone transmitter to modulate the sustained oscillations so set up. The receiving apparatus consisted of a variable contact, known as a pill-box detector, which Sir Oliver Lodge had devised, and to this was connected an Ericsson telephone receiver, then the most sensitive made. A later improvement for setting up sustained oscillations was the author’s rotating oscillation arc.
Since those memorable days of more than two decades ago, wonderful advances have been made in both of these methods of transmitting intelligence, and the end is as yet nowhere in sight. Twelve or fifteen years ago the boys began to get fun out of listening-in to what the ship and shore stations were sending and, further, they began to do a little sending on their own account. These youngsters, who caused the professional operators many a pang, were the first wireless amateurs, and among them experts were developed who are foremost in the practice of the art today.
Away back there, the spark coil and the arc lamp were the only known means for setting up oscillations at the sending end, while the electrolytic and crystal detectors were the only available means for the amateur to receive them. As it was next to impossible for a boy to get a current having a high enough voltage for operating an oscillation arc lamp, wireless telephony was out of the question for him, so he had to stick to the spark coil transmitter which needed only a battery current to energize it, and this, of course, limited him to sending Morse signals. As the electrolytic detector was cumbersome and required a liquid, the crystal detector which came into being shortly after was just as sensitive and soon displaced the former, even as this had displaced the coherer.
A few years ahead of these amateurs, that is to say in 1905, J. A. Fleming, of England, invented the vacuum tube detector, but ten more years elapsed before it was perfected to a point where it could compete with the crystal detector. Then its use became general and workers everywhere sought to, and did improve it. Further, they found that the vacuum tube would not only act as a detector, but that if energized by a direct current of high voltage it would set up sustained oscillations like the arc lamp, and the value of sustained oscillations for wireless telegraphy as well as wireless telephony had already been discovered.
The fact that the vacuum tube oscillator requires no adjustment of its elements, that its initial cost is much less than the oscillation arc, besides other considerations, is the reason that it popularized wireless telephony; and because continuous waves have many advantages over periodic oscillations is the reason the vacuum tube oscillator is replacing the spark coil as a wireless telegraph transmitter. Moreover, by using a number of large tubes in parallel, powerful oscillations can be set up and, hence, the waves sent out are radiated to enormous distances.
While oscillator tubes were being experimented with in the research laboratories of the General Electric, the Westinghouse, the Radio Corporation of America, and other big companies, all the youthful amateurs in the country had learned that by using a vacuum tube as a detector they could easily get messages 500 miles away. The use of these tubes as amplifiers also made it possible to employ a loud speaker, so that a room, a hall, or an out-of-door audience could hear clearly and distinctly everything that was being sent out.
The boy amateur had only to let father or mother listen-in, and they were duly impressed when he told them they were getting it from KDKA (the Pittsburgh station of the Westinghouse Co.), for was not Pittsburgh 500 miles away! And so they, too, became enthusiastic wireless amateurs. This new interest of the grown-ups was at once met not only by the manufacturers of apparatus with complete receiving and sending sets, but also by the big companies which began broadcasting regular programs consisting of music and talks on all sorts of interesting subjects.
This is the wireless, or radio, as the average amateur knows it today. But it is by no means the limit of its possibilities. On the contrary, we are just beginning to realize what it may mean to the human race. The Government is now utilizing it to send out weather, crop and market reports. Foreign trade conditions are being reported. The Naval Observatory at Arlington is wirelessing time signals.
Department stores are beginning to issue programs and advertise by radio! Cities are also taking up such programs, and they will doubtless be included soon among the regular privileges of the tax-payers. Politicians address their constituents. Preachers reach the stay-at-homes. Great singers thrill thousands instead of hundreds. Soon it will be possible to hear the finest musical programs, entertainers, and orators, without budging from one’s easy chair.
In the World War wireless proved of inestimable value. Airplanes, instead of flying aimlessly, kept in constant touch with headquarters. Bodies of troops moved alertly and intelligently. Ships at sea talked freely, over hundreds of miles. Scouts reported. Everywhere its invisible aid was invoked.
In time of peace, however, it has proved and will prove the greatest servant of mankind. Wireless messages now go daily from continent to continent, and soon will go around the world with the same facility. Ships in distress at sea can summon aid. Vessels everywhere get the day’s news, even to baseball scores. Daily new tasks are being assigned this tireless, wireless messenger.
Messages have been sent and received by moving trains, the Lackawanna and the Rock Island railroads being pioneers in this field. Messages have also been received by automobiles, and one inventor has successfully demonstrated a motor car controlled entirely by wireless. This method of communication is being employed more and more by newspapers. It is also of great service in reporting forest fires.
Colleges are beginning to take up the subject, some of the first being Tufts College, Hunter College, Princeton, Yale, Harvard, and Columbia, which have regularly organized departments for students in wireless.
Instead of the unwieldy and formidable looking apparatus of a short time ago, experimenters are now vying with each other in making small or novel equipment. Portable sets of all sorts are being fashioned, from one which will go into an ordinary suitcase, to one so small it will easily slip into a Brownie camera. One receiver depicted in a newspaper was one inch square! Another was a ring for the finger, with a setting one inch by five-eighths of an inch, and an umbrella as a “ground.” Walking sets with receivers fastened to one’s belt are also common. Daily new novelties and marvels are announced.
Meanwhile, the radio amateur to whom this book is addressed may have his share in the joys of wireless. To get all of these good things out of the ether one does not need a rod or a gun–only a copper wire made fast at either end and a receiving set of some kind. If you are a sheer beginner, then you must be very careful in buying your apparatus, for since the great wave of popularity has washed wireless into the hearts of the people, numerous companies have sprung up and some of these are selling the veriest kinds of junk.
And how, you may ask, are you going to be able to know the good from the indifferent and bad sets? By buying a make of a firm with an established reputation. I have given a few offhand at the end of this book. Obviously there are many others of merit–so many, indeed, that it would be quite impossible to get them all in such a list, but these will serve as a guide until you can choose intelligently for yourself.
I. HOW TO BEGIN WIRELESS
Kinds of Wireless Systems–Parts of a Wireless System–The Easiest Way to Start–About Aerial Wire Systems–About the Receiving Apparatus–About Transmitting Stations–Kinds of Transmitters–The Spark Gap Wireless Telegraph Transmitter–The Vacuum Table Telegraph Transmitter–The Wireless Telephone Transmitter.
II. PUTTING UP YOUR AERIAL
Kinds of Aerial Wire Systems–How to Put Up a Cheap Receiving Aerial–A Two-wire Aerial–Connecting in the Ground–How to Put up a Good Aerial–An Inexpensive Good Aerial–The Best Aerial That Can be Made–Assembling the Aerial–Making a Good Ground.
III. SIMPLE TELEGRAPH AND TELEPHONE RECEIVING SETS
Assembled Wireless Receiving Sets–Assembling Your Own Receiving Set–The Crystal Detector–The Tuning Coil–The Loose Coupled Tuning Coil–Fixed and Variable Condensers–About Telephone Receivers– Connecting Up the Parts–Receiving Set No. 2–Adjusting the No. 1 Set–The Tuning Coil–Adjusting the No. 2 Set.
IV. SIMPLE TELEGRAPH SENDING SETS
A Cheap Transmitting Set (No. 1)–The Spark Coil–The Battery–The Telegraph Key–The Spark Gap–The Tuning Coil–The High-tension Condenser–A Better Transmitting Set (No. 2)–The Alternating Current Transformer–The Wireless Key–The Spark Gap–The High-tension Condenser–The Oscillation Transformer–Connecting Up the Apparatus–For Direct Current–How to Adjust Your Transmitter. Turning With a Hot Wire Ammeter–To Send Out a 200-meter Wave Length–The Use of the Aerial Switch–Aerial Switch for a Complete Sending and Receiving Set–Connecting in the Lightning Switch.
V. ELECTRICITY SIMPLY EXPLAINED
Electricity at Rest and in Motion–The Electric Current and its Circuit–Current and the Ampere–Resistance and the Ohm–What Ohm’s Law Is–What the Watt and Kilowatt Are–Electromagnetic Induction–Mutual Induction–High-frequency Currents–Constants of an Oscillation Circuit–What Capacitance Is–What Inductance Is–What Resistance Is–The Effect of Capacitance.
VI. HOW THE TRANSMITTING AND RECEIVING SETS WORK
How Transmitting Set No. 1 Works–The Battery and Spark Coil Circuit–Changing the Primary Spark Coil Current Into Secondary Currents–What Ratio of Transformation Means–The Secondary Spark Coil Circuit–The Closed Oscillation Circuit–How Transmitting Set No. 2 Works-With Alternating Current–With Direct Current–The Rotary Spark Gap–The Quenched Spark Gap–The Oscillation Transformer–How Receiving Set No. 1 Works–How Receiving Set No. 2 Works.
VII. MECHANICAL AND ELECTRICAL TUNING
Damped and Sustained Mechanical Vibrations–Damped and Sustained Oscillations–About Mechanical Tuning–About Electric Tuning.
VIII. A SIMPLE VACUUM TUBE DETECTOR RECEIVING SET
Assembled Vacuum Tube Receiving Set–A Simple Vacuum Tube Receiving Set–The Vacuum Tube Detector–Three Electrode Vacuum Tube Detector–The Dry Cell and Storage Batteries–The Filament Rheostat–Assembling the Parts–Connecting Up the Parts–Adjusting the Vacuum Tube Detector Receiving Set.
IX. VACUUM TUBE AMPLIFIER RECEIVING SETS
A Grid Leak Amplifier Receiving Set. With Crystal Detector–The Fixed Resistance Unit, or Grid Leak–Assembling the Parts for a Crystal Detector Set–Connecting up the Parts for a Crystal Detector–A Grid Leak Amplifying Receiving Set With Vacuum Tube Detector–A Radio Frequency Transformer Amplifying Receiving Set–An Audio Frequency Transformer Amplifying Receiving Set–A Six Step Amplifier Receiving Set with a Loop Aerial–How to Prevent Howling.
X. REGENERATIVE AMPLIFICATION RECEIVING SETS
The Simplest Type of Regenerative Receiving Set–With Loose Coupled Tuning Coil–Connecting Up the Parts–An Efficient Regenerative Receiving Set. With Three Coil Loose Coupler–The A Battery Potentiometer–The Parts and How to Connect Them Up–A Regenerative Audio Frequency Amplifier–The Parts and How to Connect Them Up.
XI. SHORT WAVE REGENERATIVE RECEIVING SETS
A Short Wave Regenerative Receiver, with One Variometer and Three Variable Condensers–The Variocoupler–The Variometer–Connecting Up the Parts–Short Wave Regenerative Receiver with Two Variometers and Two Variable Condensers–The Parts and How to Connect Them Up.
XII. INTERMEDIATE AND LONG WAVE REGENERATIVE RECEIVING SETS
Intermediate Wave Receiving Sets–Intermediate Wave Set With Loading Coils–The Parts and How to Connect Them Up–An Intermediate Wave Set with Variocoupler Inductance Coils–The Parts and How to Connect Them Up–A Long Wave Receiving Set–The Parts and How to Connect Them Up.
XIII. HETERODYNE OR BEAT LONG WAVE TELEGRAPH RECEIVING SET
What the Heterodyne or Beat Method Is–The Autodyne or Self-heterodyne Long Wave Receiving Set–The Parts and Connections of an Autodyne or Self-heterodyne, Receiving Set–The Separate Heterodyne Long Wave Receiving Set–The Parts and Connections of a Separate Heterodyne Long Wave Receiving Set.
XIV. HEADPHONES AND LOUD SPEAKERS
Wireless Headphones–How a Bell Telephone Receiver is Made–How a Wireless Headphone is Made–About Resistance, Turns of Wire and Sensitivity of Headphones–The Impedance of Headphones–How the Headphones Work–About Loud Speakers–The Simplest Type of Loud Speaker–Another Simple Kind of Loud Speaker–A Third Kind of Simple Loud Speaker–A Super Loud Speaker.
XV. OPERATION OF VACUUM TUBE RECEPTORS
What is Meant by Ionization–How Electrons are Separated from Atoms–Action of the Two Electrode Vacuum Tube–How the Two Electrode Tube Acts as a Detector–How the Three Electrode Tube Acts as a Detector–How the Vacuum Tube Acts as an Amplifier–The Operation of a Simple Vacuum Tube Receiving Set–Operation of a Regenerative Vacuum Tube Receiving Set–Operation of Autodyne and Heterodyne Receiving Sets–The Autodyne, or Self-Heterodyne Receiving Set–The Separate Heterodyne Receiving Set.
XVI. CONTINUOUS WAVE TELEGRAPH TRANSMITTING SETS WITH DIRECT CURRENT
Sources of Current for Telegraph Transmitting Sets–An Experimental Continuous Wave Telegraph Transmitter–The Apparatus You Need–The Tuning Coil–The Condensers–The Aerial Ammeter–The Buzzer and Dry Cell–The Telegraph Key–The Vacuum Tube Oscillator–The Storage Battery–The Battery Rheostat–The Oscillation Choke Coil–Transmitter Connectors–The Panel Cutout–Connecting Up the Transmitting Apparatus–A 100-mile C. W. Telegraph Transmitter–The Apparatus You Need–The Tuning Coil–The Aerial Condenser–The Aerial Ammeter–The Grid and Blocking Condensers–The Key Circuit Apparatus–The 5 Watt Oscillator Vacuum Tube–The Storage Battery and Rheostat–The Filament Voltmeter–The Oscillation Choke Coil–The Motor-generator Set–The Panel Cut-out–The Protective Condenser–Connecting Up the Transmitting Apparatus–A 200-mile C. W. Telegraph Transmitter–A 500-mile C. W. Telegraph Transmitter–The Apparatus and Connections– The 50-watt Vacuum Tube Oscillator–The Aerial Ammeter–The Grid Leak Resistance–The Oscillation Choke Coil–The Filament Rheostat–The Filament Storage Battery–The Protective Condenser–The Motor-generator–A 1000-mile C. W. Telegraph Transmitter.
XVII. CONTINUOUS WAVE TELEGRAPH TRANSMITTING SETS WITH ALTERNATING CURRENT
A 100-mile C. W. Telegraph Transmitting Set–The Apparatus Required–The Choke Coils–The Milli-ammeter–The A. C. Power Transformer–Connecting Up the Apparatus–A 200- to 500-mile C. W. Telegraph Transmitting Set-A 500- to 1000-mile C. W. Telegraph Transmitting Set–The Apparatus Required–The Alternating Current Power Transformer-Connecting Up the Apparatus.
XVIII. WIRELESS TELEPHONE TRANSMITTING SETS WITH DIRECT AND ALTERNATING CURRENTS
A Short Distance Wireless Telephone Transmitting Set–With 110-volt Direct Lighting Current–The Apparatus You Need–The Microphone Transmitter–Connecting Up the Apparatus–A 25- to 50-mile Wireless Telephone Transmitter–With Direct Current Motor Generator–The Apparatus You Need–The Telephone Induction Coil–The Microphone Transformer–The Magnetic Modulator–How the Apparatus is Connected Up–A 50- to 100-mile Wireless Telephone Transmitter–With Direct Current Motor Generator–The Oscillation Choke Coil–The Plate and Grid Circuit Reactance Coils–Connecting up the Apparatus–A 100- to 200-mile Wireless Telephone Transmitter–With Direct Current Motor Generator–A 50- to 100-mile Wireless Telephone Transmitting Set–With 100-volt Alternating Current–The Apparatus You Need–The Vacuum Tube Rectifier–The Filter Condensers–The Filter Reactance Coil– Connecting Up the Apparatus–A 100- to 200-mile Wireless Telephone Transmitting Set–With 110-volt Alternating Current–Apparatus Required.
XIX. THE OPERATION OF VACUUM TUBE TRANSMITTERS
The Operation of the Vacuum Tube Oscillator–The Operation of C. W. Telegraph Transmitters with Direct Current–Short Distance C. W. Transmitter–The Operation of the Key Circuit–The Operation of C. W. Telegraph Transmitting with Direct Current–The Operation of C. W. Telegraph Transmitters with Alternating Current–With a Single Oscillator Tube–Heating the Filament with Alternating Current–The Operation of C. W. Telegraph Transmitters with Alternating Current– With Two Oscillator Tubes–The Operation of Wireless Telephone Transmitters with Direct Current–Short Distance Transmitter–The Microphone Transmitter–The Operation of Wireless Telephone Transmitters with Direct Current–Long Distance Transmitters–The Operation of Microphone Modulators–The Induction Coil–The Microphone Transformer–The Magnetic Modulator–Operation of the Vacuum Tube as a Modulator–The Operation of Wireless Telephone Transmitters with Alternating Current–The Operation of Rectifier Vacuum Tubes–The Operation of Reactors and Condensers.
XX. HOW TO MAKE A RECEIVING SET FOR $5.00 OR LESS.
The Crystal Detector–The Tuning Coil–The Headphone–How to Mount the Parts–The Condenser–How to Connect Up the Receptor.
(You can read more, if you want, of this etext … by getting it from Project Gutenberg.)
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