Radiotelegraphy: U.S. Signal Corps |
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adjustments aerial alternating current amperes amplitude antenna ammeter reading antenna circuit armature binding post C₁ capacity changes charged body closed circuit closed oscillating circuit coil connected counterpoise cuit curve damped desired wave length detector direct current direction discharge Divide by Divide electrical electromagnetic electrostatic system Electrostatic units energy farad field of force Fort Sam Houston fundamental wave length gasket ground hot-wire ammeter inch insulated kilowatt loading coil logarithmic decrement loose coupling magnetic field mast maximum microhenrys millihenry motor Multiply natural logarithm number of turns open circuit operating chest oscillation transformer oscillations per second plates plug potential primary circuit quenched spark radiation radiotelegraphy reactance receiving circuits receiving set resistance resonance rheostat secondary circuit sections shown in figure Signal Corps spark gap static field static lines surface switch telephones tions transmitting tuning units no name variable condenser variometer voltage volts wattmeter wave meter wave train wire
Popular passages
Page 80 - It is of 2-kilowatts output and is carried on a two-chest pintle wagon, one chest with the engine and generator and the other with the transmitting and the receiving apparatus. The range of these sets varies from 75 to 800 miles, depending on favorable weather conditions, time of day or night, character of the land between the sets. etc.
Page 91 - ... No. 2 back to the generator. The voltmeter is across the AC leads as shown. If the voltmeter shows voltage, but upon closing the key no spark takes place at the spark gap the snap switch in the primary circuit is probably open. The voltage, as indicated by the voltmeter, must never be more than 85. If it is desired to change the generator frequency (and the pitch of the note emitted), in order to secure greater selectivity for the set when working in the presence of other sets having about the...
Page 66 - ... where the adjustments are made by using a variable inductance ; thus the larger the number of turns in circuit the greater the inductance and the lower the frequency or the longer the wave length of the oscillations to which it is tuned, and, vice versa, the fewer the number of turns the less the inductance and the higher the frequency or the shorter the wave length of the oscillations. In this case the detector D is in a branch circuit with the condenser S and the telephones T, which is connected...
Page 89 - The aerial used with this set should have a capacity of 0.0011 mf and a natural period of 450 meters. The following detailed notes on the circuits and operation of the set have been found useful as a result of actual work in the field : POWER CIRCUITS. Referring to connection diagram 75, it is seen that DC leads marked 3 and 4 go to both receiving switches in series.
Page 93 - I. and so on, finding the best combination for every 50 meters increase in wave length up to the limit of the set. LIMITATIONS OF SYSTEM OF CODING WAVE LENGTHS. It will be noted that there is one best wave for the set, namely, about 1,000 meters. From some experiments made recently at Fort Leavenworth it is concluded that it is safe to state that, up to about 75 miles over average land, the falling off of energy due to the use of the longest wave lengths will not be so great as to prevent the use...
Page 89 - To receive, close the large double-pole switch at the top of the receiver. The plug holes marked with Roman numbers (at the right on the receiver) are connected to taps on the aerial or primary coil. The wave range of this coil is approximately as follows, with a proper aerial : The turns on the detector or loose coupling coil are variable by means of the switch located on its top, the wave range for each tap being marked. Either of the two detectors can be used by means of the switch located between...
Page 92 - and " Great " which throws the coils of this variometer from a parallel to a series connection or vice versa. This switch can only be moved to the right or left — to " Little " or to " Great " — when the index is directly opposite the dividing line between the red and the white divisions. Any attempt to throw this switch when the variometer coils are in any other position will only result in damage to the switch.
Page 74 - ... signals audible, but that it must be used in connection with some of the detectors described below. A number of forms of detectors have been invented, most of which rectify the high-frequency currents — that is, change them from alternating to direct currents by some kind of valve action — and thus render them capable of operating the telephone at an audible frequency. In figure 67 the upper curve shows several damped wave trains as in the receiving circuits, the middle curve shows them as...