Radiotelegraphy, U. S. Signal Corps1914 |
Common terms and phrases
adjustment aerial alternating current amperes amplitude antenna ammeter reading antenna circuit armature called capacity charged closed circuit closed oscillating circuit counterpoise cuit curve cycles per second damped decrement desired wave length detector direct current discharge electric electromagnetic electrostatic energy farad frequency meter fundamental wave length gaskets ground high-frequency inch increased inductively coupled inserted insulated kilowatt loading coil loosely coupled magnetic field mast maximum microhenrys millihenry motor necessary number of turns open circuit operator oscillation transformer oscillations per second pitch plates plug potential primary circuit quenched spark radiating circuit radio radiotelegraphy reactance receiving circuits receiving set resistance resonance rheostat rotating secondary circuit shown in figure shunt Signal Corps single wave length spark frequency spark gap sparking surfaces static switch telephone terminals tion transformer secondary transmitting tuning units no name variable condenser variometer vibration voltage voltmeter volts wattmeter wave meter wave train
Popular passages
Page 102 - ... shelter tent when erected, and 1 extra section for use in case one of the others becomes unserviceable. When starting to erect the mast, the four antenna wires and guys should be laid out on the ground at right angles to each other and the umbrella insulator put on the upper end of the section that is not provided with a coupling tube. This section should then be raised and eight more sections with coupling tubes added, section by section, the tenth and last section being the one provided with...
Page 105 - ... and the sparking surface be kept true and plane, as shown by a straightedge. Great care should be exercised in reassembling the gap to set the mica washers accurately on the annular surfaces of the disk and to put on enough tension with the clamping screws to render all of the gap spaces air-tight. Tuning of Sending Set The tuning of the closed and open circuits to resonance, and the determination of the correct coupling between them are the two most important adjustments in a quenched spark...
Page 110 - SHORT WAVES. Primary condenser in series. Switch on "In" contact.] LONG WAVES. Primary condenser short-circuited. [Switch not on "In" contact.] TUNING OF THE RECEIVING SET. First, the detector must be adjusted to a sensitive point by means of the test buzzer, the note of which should be clearly heard in the receiving telephones when it is held near the antenna or counterpoise wires or the coil windings. When the wave length of the sending station is known, the number of turns in the primary and secondary...
Page 110 - The coil is variable only by sections, marked 100, 200, etc., the smaller numbers to be used at the shorter wave lengths and ' the larger ones at the longer wave lengths. The position of the secondary coil within the primary — that is, the coupling — is variable, and for the sake of convenience a scale is provided so as to be able to note the different adjustments. The coupling is closest when the secondary is inside the primary, in which case the scale reading is 0. and vice versa; the coupling...
Page 110 - FIG. 79. ondary coil within the primary — that is, the coupling — is variable, and for the sake of convenience a scale is provided so as to be able to note the different adjustments. The coupling is closest when the secondary is inside the primary, in which case the scale reading is 0, and vice versa, the coupling is loosest when the secondary is drawn outside the primary and th6 scale reading is 40. SHORT WAVES. Primary condenser in series. Switch on "In
Page 68 - ... DIRECTLY CONNECTED CIRCUITS. A simple circuit for tuning the receiving antenna to the same frequency or wave length as the transmitter is shown in figure 59, 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...
Page 109 - The secondary circuit includes the secondary coil, detector, and the stopping condenser shunting the telephones. The coil is variable only by sections, marked 100, 200, etc., the smaller numbers to be used at the shorter wave lengths and the larger ones at the longer wave lengths. The position of the secondary coil within the...
Page 102 - ... type F mast equipment consists of 14 sections, each 4 feet 2 inches long, or 5 feet 2 inches over all, including the coupling tube. The 10 sections are used for the mast itself, 3 sections for the shelter tent when erected, and 1 extra section for use in case one of the others becomes unserviceable. When starting to erect the mast, the four antenna wires and guys should be laid out on the ground at right angles to each other and the umbrella insulator put on the upper end of the section that...
Page 96 - ... amperes. CODING OF WAVE LENGTHS. The great advantage of this set lies in the fact that any desired wave length from 675 to 2,220 meters can be sent out at will and if the wave length is changed after every word of a message, according to a prearranged code of wave lengths — for example, the first word sent with 700 meters, the next with 2,100, the next with 1,400, etc. — it will be difficult for any eavesdropping operator who has not the wavelength code to follow the changes of wave length...
Page 93 - Referring to connection diagram 75, it is seen that DC leads marked 3 And 4 go to both receiving switches in series. It is therefore necessary to have the main switches of both receiving sets in the same position — that is, cut off — when sending, even though one receiving set may have no aerial wire connected to it. A flash...