Radio room

“ We'll try to contact phone stations wherever possible for this program we have in mind. Most of the stuff will be put on tape, and Dad will probably want you to prepare typed copies, too. You can do enough to take a big load off the rest of us."
"I'll be happy to try."
They spent the rest of the day in the radio room of the science shack. Ken taught Maria the simple operations of turning on the transmitter and receiver, of handling the tuning controls, and the proper procedure for making and receiving calls. ”

“ Where the electric light tube would have contained only the filament, these tubes at which they were looking contained also a plate and a grid—the latter being that magical invention which had worked a complete revolution in the science of radio and had made broadcasting possible. ”

“ The winning of the prizes, the first by Bob and the second by Joe, with honorable mention for Jimmy, was a spur to fresh efforts in mastering the wonders of radio. This they carried out at Ocean Point, a seashore resort, at which they spent their vacation. How they advanced to the use of the vacuum tube receiving set from their first crystal set; their experiences in the wireless room of a seashore station; their narrow escape from death on the night of a roaring gale ”

“ They’re coming into the ranks by thousands every day. Nobody can keep count of them, but they must run into the millions.
“And they’re great in quality as well as quantity,” he continued, warming to his favorite subject. “The President of the United States has a radio receiving set on his desk. There’s one in the office of every one of the ten Cabinet members. The Secretary of the Navy is sending out wireless messages every day to vessels scattered in all parts of the globe. The head of the army is keeping in touch by radio with every fort and garrison and corps area in the United States. ”

“ He cleared his throat and looked around with his well-known lecture-room air.
“Now that the author of the strange phenomena which have confronted us in this house has been apprehended,” he said, “explanations, and such further investigations as are needed to completely clear up the mystery, are in order.
“You are all aware that the manifestations we have witnessed were under the control of an operator established in an old farmhouse eight miles west of here, and that the mechanism he used was a powerful and complicated radio set. ”

“ Radio is certainly getting to be a country-wide craze. Only the other day I was at one of the big broadcasting stations, and the manager told me that they were actually having trouble to get performers, there is such a demand for them. They seem to be especially hard up for novelty acts—something out of the ordinary. ”

“ If an interfering station butts in, just decrease the coupling between primary and secondary and then tune again the two circuits. You can feel pretty sure of cutting out the interference and getting clearly just the station that you want.”
“That’s mighty good dope,” said Bob. “I’ve had that trouble more than once and haven’t been quite clear as to the best way of getting around it.”
“Then too,” went on the radio expert, “you must be careful in adjusting the tickler that gives the regenerative effect. Start in slowly by turning the control knob toward the maximum. ”

“ So I’ll say it all in one sentence—the radio is the most wonderful invention ever conceived by the mind of man.”
“You don’t need to prove it to us,” laughed Bob. “It’s simply a miracle, and we become more convinced of that every day. I’m mighty glad I was born in this age of the world.”
The boys crowded around Mr. Harvey as he explained to Larry and Tim in as simple a way as possible the radio apparatus of the station. ”

“ This “feed-back” regeneration enormously increased the loudness of the receiving signals, and its value to the boys was demonstrated one night when the air was unusually free of static and they clearly heard the signals from Nauen, Germany, and the Eiffel Tower, Paris. ”

“ The sending is from pencil lines on paper, the reception on electrolytic paper.
The machine is also made with a glass cylinder to send from a picture transparency, and to receive on photographic paper. It must, therefore, be used in a dark or subdued lighted room to receive.
Each machine is capable of the very highest quality of work of its particular kind, and is simple and easy to operate.
108
109 Radio Vision The machines here shown are the laboratory models used in the development of Radio Vision and Radio Movies for the reception in the home of broadcast studio performances, i. ”

“ We may, one day, obtain far greater sensitivity of direction, greater carrying power, from small initial output with a degree of selectivity almost infinite, in comparison with modern working.
To use a light beam along which we can talk, to use a light beam initially and to turn it into light when required, is by no means difficult; it suggests the direct method of wireless vision, but from the mechanical aspect the problem is still less complicated. The difficulties of Radio Television to-day are constructional; in the far future it may be a question of pure physics. ”

“ Truly the science of radio-telegraphy has made rapid strides since the days of the “coherer,” until now, after the war, it is the most advanced in our human civilisation, and at the same time full of romance. Not a month passes but something new is discovered in that high-built, well-knit laboratory, where daily the keenest brains of wireless experimenters are at work devising, testing, and too often scrapping new instruments, new circuits, and new devices in order to improve and render less complicated both the ordinary wireless by Morse, and that modern marvel, the wireless telephone. ”

“ Millions of messages going in all directions, crossing and recrossing one another, as is done every day by wire, are probably an impossibility by wireless telephony. Weird and little-understood conditions of the ether, static electricity, radio disturbances, make wireless work uncertain, and such a thing as twenty-four-hour service, seven days in the week, can probably never be guaranteed. In radio communication all must use a common medium, and as its use increases, so also do the difficulties. The privacy of the wire is also lacking with the wireless telephone. ”

“ You can see that very few telephone messages can be sent in the long-wave-length part of the radio range and many more, although not very many after all, in the short wave-length part of the radio range. You can also see why it is desirable to keep amateurs in the short wave-length part of the range where more of them can transmit simultaneously without interfering with each other or with commercial radio stations. ”

“ Just the same, only in radio telephony we are confronted by a problem not met with in wireless telegraphy. We have not only to transmit sound, such as isolated dots and dashes, but to send through the air every rise and fall and inflection of the human voice just as it is recorded in the minute lines of a phonographic record. ”

“ I told him about my visitor and the repair job. "What I did was add a modulator-oscillator-power amplifier, and a few feet of wire for an antenna, coiled around inside the case."
"So what does that make it?"
"Simple. It makes it a radio transmitter. Not only will he hear what the horses are saying, but anyone in town with a radio tuned to that frequency will, too."
"And where does that get you?" The sergeant was still puzzled but not bored now. ”

“ Although a war invention, its peacetime service will be to save lives. It is a very simple matter to rig up a wireless-telegraph system that will send messages to a considerable distance, and simpler still to rig up a receiving-set. European governments have always discouraged amateur radiotelegraphy, but in this country restrictions used to be so slight that almost any one could set up and use a radio set, both for receiving and for transmitting. ”

“ Tom wanted to know.
"Because, up to the present, no way has been found of utilizing in radio telephony the entire energy of the electric waves sent out," replied Professor Chadwick. "Only the variations in the waves can be detected, or transformed into sound at the receiving end of a radio telephone system. Therefore an immense amount of electrical energy has to be manufactured in order that the voice vibrations may register their variations as powerfully as possible." ”

“ The different light values of the picture are changed into electric values in light cell 4, and broadcast. A rotating perforated disc, (3) interposed between the lens and light cell, produces a pulsating direct current which can immediately be amplified through the usual radio transformers, on its way to the broadcasting set.
In the radio camera (second illustration) a photographic negative (1) is used and a pencil of light from lamp 2. The rotating plates (3) draw the lines and the radio signals vary the light intensities of the lamp to give gradations of exposure on the negative plate. ”

“ In an emergency, any wire of sufficient length can be used for an antenna; for example, barbed wire, electrical wire, fence wire, and metal-cored clothesline. Communication has been successful using metal house gutters and even metal bed springs. A radio operator's mission is not completed until communication is established. f. Grounding. A good electrical ground is needed for two reasons: first, to protect the operator and his equipment; and second, as a radio frequency ground needed by some antennas to function properly. ”

“ An LRS team that can see everything and report nothing is useless. LRSUs normally use high-frequent radios to report information and receive instructions. Because of the complex nature of using the HF radio spectrum, a LRSU radio operator must have an in-depth knowledge of radios, antennas, and radio wave propagation.
D-1. HIGH-FREQUENCY RADIO FUNDAMENTALS For successful communication, HF radio performance depends on the type of emission (voice or burst device) , transmitter power output, and type of antenna. The challenge facing HF radio operators is tremendous. ”

“ If you follow directions carefully. And with the new outfit a loop is just as effective an antenna as an outside aerial. They say, too, that to catch broadcasting for not more than twenty-five miles, not even a loop is needed, the circuits themselves acting as the absorbers of energy.”
“I’m going to try it,” declared Jessie, with more confidence. “But I feel that I understand so little about the various forms of radio, after all.”
“You have nothing on me there,” laughed the operator. “I am learning something new all the time. ”

“ Herb took him up. “Look at telephone and telegraph and electric lighting systems. There have been changes in them, of course, but beside the rapid-fire changes of radio, they seem to have been standing still.”
“There haven’t been any changes to speak of in the electric lighting systems for the last fifteen 96 years or more,” said Bob. “And the telephone has stayed just about the same, too.”
“There’s no doubt about it,” said Joe. “Radio has got ’em all beat as far as a field for experiment is concerned. Say,” he added fervently, “aren’t you glad you weren’t born a hundred years ago?” ”

“ And new means for modulating electric current by changing light values may be expected when the American boy starts to play with this new toy.
There has been a veritable army of engineers engaged in the development of radio as a service to the ear, while relatively few engineers have been developing radio as a service to the eye.
It is believed that the distant electric modulation of light for many purposes will soon become a common phenomena and eventually of inestimable service in science, in engineering, in industry, and in the home. ”

“ In that way, a single pair of wires can be used for transmitting, simultaneously and without any interference, several different telephone conversations. It takes very much less power than would radio transmission and the conversations are secret. The ordinary telephone conversation can go on at the same time without any interference with those which are being carried by the modulations in high-frequency currents. ”

“ When a sub is heard and located, the listeners call the net-layers by radio, and they go to the spot at a thirty-knot speed. As they approach they soon drown out the sound of the sub, but their speed and number enables them to surround the area in which she is known to be, for she won’t have time to go far from where she was last heard. Paying out their nets, they hem her in and keep the ring of nets closed round her till the area is raked with trailing wires and other electromagnetic detectors which will enable the chasers to concentrate their depth charges with the certainty of a kill. ”

“ We send sound, music by radio waves across half the world from our broadcasting stations. We send light, pictures, across the world from our television stations. We do that by changing the wave length of the light-vibrations to make them radio vibrations, flashing them out thus over the world, to receivers which alter their wave-lengths again and change them back into light-vibrations. ”

“ What for?” cried Bob.
And, “Yes, what for?” echoed others. Mr. Hampton and Rafaela, who already had been admitted to the secret, alone remained silent.
“There’s a man down there who also has been experimenting on radio,” Jack said, “but along different lines. He is trying to find out the laws controlling radio waves for the transmission of vision. Well, maybe, I didn’t put that just right. But this is what he’s after: He’s trying to evolve a radio device for the broadcasting of scenes. ”