Radios

“ From the telephone to radio constituted but another such step, and we are now enjoying radio broadcast from stations thousands of miles away. Every time you have an Xray photograph taken you are bombarded, not by rays, but by actual particles that go right through the walls of the tube, which particles are just as real as if they were bullets or bricks, the only difference being that they are smaller. Thus our scientists lead up to the way of sending solids through space. ”

“ 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. ”

“ 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. ”

“ The radio-telephone does not transmit the human voice. It reproduces near the ears of the listener similar motions of the air molecules and hence causes in the ears of the listener the same sensations of sound as if he were listening directly to the speaker. This reproduction takes place almost instantaneously so great is the speed with which the electrical effects travel outward from the sending antenna. If you wish to understand radio-telephony you must know something of the mechanism by which the voice is produced and something of the peculiar or characteristic properties of voice sounds. ”

“ For the chief on the 35th floor hearing of the South Tower collapse and taking subsequent action, see FDNY interview 23, Chief (Jan. 23, 2004) . For firefighters beginning to evacuate because of these chiefs, see, e.g., FDNY interview 16, Battalion 1 (Jan. 20, 2004) ; FDNY interview, transcript 9, Battalion 6, Dec. 5, 2001.
166. For radios not working in high-rise environments, see FDNY interview 9, Battalion 8 (Jan. 9, 2004) ; FDNY interview 13, Battalion 1 (Jan. 13, 2004) . For tactical 1 being overburdened, see FDNY interview 16, Battalion 1 (Jan. 20, 2004) . ”

“ If a telephone-receiver diaphragm can be made to vibrate in accordance with the variations in signal intensity then the air adjacent to that diaphragm will be set into vibration and these vibrations will be just like those which the human voice set up in the air molecules near the mouth of the speaker. All the different systems of receiving radio-telephone signals are merely different methods of getting a current which will affect the telephone receiver in conformity with the variations in signal strength. ”

“ 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." ”

“ 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. ”

“ Maybe thar is some way, except by water, in spite of what he said."
"Maybe there is," said Jack. "It seems a shame to think of all that rich stuff lying there neglected and unobtainable."
"It does indeed," agreed the professor. "In that sample I find traces of metals from which filaments for electric lights could be made and substances invaluable in medicine for X-ray purposes as well as the Z.2.X. which your father is convinced would make the radio telephone as practical as the wireless telegraph." ”

“ 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. ”

“ The range of intermediate wave receptors is such that they will receive amateur, broadcasting, ship and shore Navy, commercial, Arlington's time and all other stations using spark telegraph damped waves or arc or vacuum tube telephone continuous waves but not continuous wave telegraph signals, unless these have been broken up into groups at the transmitting station. ”

“ Giddings.
"Practically the same, dad. The wireless transmitter, like that of the wire telephone, contains a sensitive diaphragm which your voice strikes and sets to vibrating. These vibrations compress and release a capsule of carbon granules which agitate and set in motion an electrical current in two magnets connecting with them. The magnets convey the sound-waves in the form of electrical waves, along wires out to the tip of each wing, where the wires hang down a little way. When a message comes in it is caught by a webbing of antennae wires in our wings." ”

“ Not only is the vacuum tube a detector of electric wave signals and speech and music but it can also be used to amplify them, that is, to make them stronger and, hence, louder in the telephone receiver and further its powers of amplification are so great that it will reproduce them by means of a loud speaker, just as a horn amplifies the sounds of a phonograph reproducer, until they can be heard by a room or an auditorium full of people. ”

“ A telephone receiver is connected across the terminals of the detector. When the electromagnetic waves from the transmitting station strike the aerial of the receiving station, they set up therein a series of high frequency oscillations, corresponding to the Morse signals emitted from the transmitter. The oscillations flow back and forth through the aerial and ground, striking the mineral detector on their journey. The high frequency oscillations are alternating currents, because they reverse their direction many thousand times per second. ”

“ 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?” ”

“ A lot of the little facts I knew had not been picked up in the Corps. One fact—normally of interest only to warpdrive technicians—concerns the curious propagation of radiation in warpspace. Radio waves in particular. They just don't go anyplace. If you broadcast on one frequency you get a strong return signal on all frequencies, as if the radio waves had been squeezed out thin and bounced right back. ”

“ Inside was a complete radio receiving set, with vacuum tube detector and batteries in perfect working order. Between the roots of the tree an 182 iron pipe had been driven into the earth to act as a ground. The antenna was strung from top to bottom of the tree on the side away from the path, and there was nothing to differentiate the box from an ordinary wire telephone set, except that it was slightly larger. ”

“ Nearly all the big wireless companies have great stations fitted with powerful telephone transmitters and at given hours of the day and night they send out songs by popular singers, dance music by jazz orchestras, fashion talks by and for the ladies, agricultural reports, government weather forecasts and other interesting features. Then by simply shifting the slide on your tuning coil you can often tune-in someone who is sending Morse, that is, messages in the dot and dash code, or, perhaps a friend who has a wireless telephone transmitter and is talking. ”

“ Audio radio engineers have been working in the very limited audio-frequency band below, say, ten thousand cycles, whereas the workable range where light instead of sound is employed goes away up to millions of cycles. It is confidently predicted that the next great development in radio is in this area. ”

“ Electrical oscillations, it will be remembered, are alternating currents of very high frequency. They are generated in the aerial of the receiving station by the action of the waves coming from the distant transmitting station. These currents are exceedingly feeble, too feeble in fact to operate any form of electrical apparatus except a telephone receiver, which is one of the most sensitive instruments in existence. ”

“ To get music by radio, a microphone converts sound into electrical modulation, which, carried by radio to distant places, is then changed back into sound and we hear the music.
To get pictures by radio, a sensitive cell converts light into electrical current, and at radio distances changes these currents back into light values, and one may see the distant scene; for light is the thing of which pictures are made, as music is made of sound. ”

“ 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. ”

“ The fleet circled Terra once more, swung high for the long dive, and then came howling down on a long slant, while Dusty took the radio and cried: "Junior Spacemen of The Space Patrol, Attention!"
The radio, powered by machinus forces, hammered down and blanketed the radio broadcast stations. It broke up the video screens in a mash of spots, flecks and snowflakes. Dusty's voice roared into telephone lines and onto the commercial radio links and chattered indistinctly in direction-finding equipment and made incomprehensible squiggles clutter the radar screens. ”

“ With modern machines in that ice hangar, this little band of explorers could tap the air of the civilized latitudes and bring its music across thousands of miles of snow barrens. A turn of the dial in the ship’s radio-room, and the long arm of radio reached forth and plucked music out of the air, the latest news from America’s metropolitan cities, tunes from Broadway and personal messages from well-wishers. ”

“ The signal which radiates out from the transmitting antenna carries all the little variations in pitch and loudness of the human voice. When this signal reaches the distant antenna it establishes in that antenna circuit a current of high frequency which has just the same variations as did the current in the antenna at the sending station. The human voice isn’t there. ”

“ The receiving station forms an exact counterpart of the transmitter, and the train of actions taking place are the reverse of those of the latter. The purpose of the transmitter is to change ordinary electric currents into electrical oscillations and thus set up electric waves, while the receptor converts the waves into oscillations and thence into currents which are capable of manifesting themselves in a telephone receiver. ”

“ 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. ”

“ Perhaps the next time the radio set begins to howl as if a dozen cat fights were mewling inside of the loud speaker, it is not static that is interfering with the reception from the broadcasting station, but a newspaper photograph which is being sent through the air. ”

“ A little later they stood entranced in the Convention Hall before a new, beautifully modeled radio amplifier, so massive that the volume of music it poured forth actually seemed to cause vibration in the walls of the great room in which they stood.
One of the most interesting features was the radio-controlled automobile. The crowd before this almost incredible invention was so dense that the operator was handicapped in his demonstration.
The car was about seven feet in length, with a cylindrical mass of wire rising about six feet above its body. ”

“ Considering the signaling apparatus of the telephones alone, therefore, each telephone was equipped with a power plant for generating currents used by that station in signaling other stations, the prime mover being the muscles of the user applied to the turning of a crank on the side of the instrument; and also with a current-consuming device in the form of a polarized electromagnetic bell adapted to receive the currents generated at other stations and to convert a portion of their energy into audible signals. ”