DISCHARGE.--(1) A faintly luminous discharge that takes place from the positive pointed terminal of an induction coil, or other high potential apparatus; is termed abrush discharge. (2) A continuous discharge between the terminals of a high potential apparatus is termed aconvective discharge. (3) The sudden breaking-down of the air between the balls forming the spark gap is termed adisruptive discharge; also called anelectric spark, or justsparkfor short. (4) When a tube has a poor vacuum, or too large a battery voltage, it glows with a blue light and this is called ablue glow discharge.
DISRUPTIVE DISCHARGE.--SeeDischarge.
DISTRESS CALL. [Morse code:] ...---... (SOS).
DISTRIBUTED CAPACITY.--SeeCapacity, Distributed.
DOUBLE HUMP RESONANCE CURVE.--A resonance curve that has two peaks or humps which show that the oscillating currents which are set up when the primary and secondary of a tuning coil are closely coupled have two frequencies.
DUO-LATERAL COILS.--SeeCoils, Inductance.
DUPLEX COMMUNICATION.--A wireless telephone system with which it is possible to talk between both stations in either direction without the use of switches. This is known as theduplex system.
EARTH CAPACITY.--An aerial counterpoise.
EARTH CONNECTION.--Metal plates or wires buried in the ground or immersed in water. Any kind of means by which the sending and receiving apparatus can be connected with the earth.
EDISON STORAGE BATTERY.--SeeStorage Battery, Edison.
ELECTRIC ENERGY.--The power of an electric current.
ELECTRIC OSCILLATIONS.--SeeOscillations, Electric.
ELECTRIC SPARK.--SeeDischarge, Spark.
ELECTRICITY, NEGATIVE.--The opposite ofpositive electricity. Negative electricity is formed of negative electrons which make up the outside particles of an atom.
ELECTRICITY, POSITIVE.--The opposite ofnegative electricity. Positive electricity is formed of positive electrons which make up the inside particles of an atom.
ELECTRODES.--Usually the parts of an apparatus which dip into a liquid and carry a current. The electrodes of a dry battery are the zinc and carbon elements. The electrodes of an Edison storage battery are the iron and nickel elements, and the electrodes of a lead storage battery are the lead elements.
ELECTROLYTES.--The acid or alkaline solutions used in batteries.
ELECTROMAGNETIC WAVES.--SeeWaves, Electric.
ELECTROMOTIVE FORCE.--Abbreviatedemf. The force that drives an electric current along a conductor. Also loosely calledvoltage.
ELECTROMOTIVE FORCE, COUNTER.--The emf. that is set up in a direction opposite to that in which the current is flowing in a conductor.
ELECTRON.--(1) A negative particle of electricity that is detached from an atom. (2) A negative particle of electricity thrown off from the incandescent filament of a vacuum tube.
ELECTRON FLOW.--The passage of electrons between the incandescent filament and the cold positively charged plate of a vacuum tube.
ELECTRON RELAY.--SeeRelay, Electron.
ELECTRON TUBE.--A vacuum tube or a gas-content tube used for any purpose in wireless work. SeeVacuum Tube.
ELECTROSE INSULATORS.--Insulators made of a composition material the trade name of which isElectrose.
ENERGY, ELECTRIC.--SeeElectric Energy.
ENERGY UNIT.--Thejoule, which see,Page 308[Appendix: Definitions of Electric and Magnetic Units].
FADING.--The sudden variation in strength of signals received from a transmitting station when all the adjustments of both sending and receiving apparatus remain the same. Also calledswinging.
FARAD.--The capacitance of a condenser in which a potential difference of 1 volt causes it to have a charge of 1 coulomb of electricity.
FEED-BACK ACTION.--Feeding back the oscillating currents in a vacuum tube to amplify its power. Also calledregenerative action.
FERROMAGNETIC CONTROL.--SeeMagnetic Amplifier.
FILAMENT.--The wire in a vacuum tube that is heated to incandescence and which throws off electrons.
FILAMENT RHEOSTAT.--SeeRheostat, Filament.
FILTER.--Inductance coils or condensers or both which (1) prevent troublesome voltages from acting on the different circuits, and (2) smooth out alternating currents after they have been rectified.
FILTER REACTOR.--SeeReactor, Filter.
FIRE UNDERWRITERS.--SeeCode, National Electric.
FIXED GAP.--SeeGap.
FLEMING VALVE.--A two-electrode vacuum tube.
FORCED OSCILLATIONS.--SeeOscillations, Forced.
FREE OSCILLATIONS.--SeeOscillations, Free.
FREQUENCY, AUDIO.--(1) An alternating current whose frequency is low enough to operate a telephone receiver and, hence, which can be heard by the ear. (2) Audio frequencies are usually around 500 or 1,000 cycles per second, but may be as low as 200 and as high as 10,000 cycles per second.
GAP, FIXED.--One with fixed electrodes.
GAP, NON-SYNCHRONOUS.--A rotary spark gap run by a separate motor which may be widely different from that of the speed of the alternator.
GAP, QUENCHED.--(1) A spark gap for the impulse production of oscillating currents. (2) This method can be likened to one where a spring is struck a single sharp blow and then continues to set up vibrations.
GAP, ROTARY.--One having fixed and rotating electrodes.
GAP, SYNCHRONOUS.--A rotary spark gap run at the same speed as the alternator which supplies the power transformer. Such a gap usually has as many teeth as there are poles on the generator. Hence one spark occurs per half cycle.
GAS-CONTENT TUBE.--SeeVacuum Tube.
GENERATOR TUBE.--A vacuum tube used to set up oscillations. As a matter of fact it does notgenerateoscillations, but changes the initial low voltage current that flows through it into oscillations. Also called anoscillator tubeand apower tube.
GRID BATTERY.--SeeBattery C.
GRID CHARACTERISTICS.--The various relations that could exist between the voltages and currents of the grid of a vacuum tube, and the values which do exist between them when the tube is in operation. These characteristics are generally shown by curves.
GRID CONDENSER.--SeeCondenser, Grid.
GRID LEAK.--A high resistance unit connected in the grid lead of both sending and receiving sets. In a sending set it keeps the voltage of the grid at a constant value and so controls the output of the aerial. In a receiving set it controls the current flowing between the plate and filament.
GRID MODULATION.--SeeModulation, Grid.
GRID POTENTIAL.--The negative or positive voltage of the grid of a vacuum tube.
GRID VOLTAGE.--SeeGrid Potential.
GRINDERS.--The most common form ofStatic,which see. They make a grinding noise in the headphones.
GROUND.--SeeEarth Connection.
GROUND, AMATEUR.--A water-pipe ground.
GROUND, WATERPIPE.--A common method of grounding by amateurs is to use the waterpipe, gaspipe or radiator.
GUIDED WAVE TELEPHONY.--SeeWired Wireless.
HARD TUBE.--A vacuum tube in which the vacuum ishigh,that is, exhausted to a high degree.
HELIX.--(1) Any coil of wire. (2) Specifically a transmitter tuning inductance coil.
HENRY.--The inductance in a circuit in which the electromotive force induced is 1 volt when the inducing current varies at the rate of 1 ampere per second.
HETERODYNE RECEPTION.--(1) Receiving by thebeatmethod. (2) Receiving by means of superposing oscillations generated at the receiving station on the oscillations set up in the aerial by the incoming waves.
HETERODYNE RECEPTOR.--SeeReceptor, Heterodyne.
HIGH FREQUENCY CURRENTS.--SeeCurrents, High Frequency.
HIGH FREQUENCY RESISTANCE.--SeeResistance, High Frequency.
HIGH POTENTIAL CURRENTS.--SeeCurrents, High Potential.
HIGH VOLTAGE CURRENTS.--SeeCurrents, High Potential.
HONEYCOMB COILS.--SeeCoils, Inductance.
HORSE-POWER.--Used in rating steam machinery. It is equal to 746 watts.
HOT WIRE AMMETER.--SeeAmmeter, Hot Wire.
HOWLING.--Where more than three stages of radio amplification, or more than two stages of audio amplification, are used howling noises are apt to occur in the telephone receivers.
IMPEDANCE.--An oscillation circuit hasreactanceand alsoresistance,and when these are combined the total opposition to the current is calledimpedance.
INDUCTANCE COILS.--SeeCoils, Inductance.
INDUCTANCE COIL, LOADING.--SeeCoil, Loading Inductance.
INDUCTIVE COUPLING.--SeeCoupling, Inductive.
INDUCTIVE REACTANCE.--SeeReactance, Inductive.
INDUCTION COIL.--SeeCoil, Induction.
INDUCTION, MUTUAL.--Induction produced between two circuits or coils close to each other by the mutual interaction of their magnetic fields.
INSULATION.--Materials used on and around wires and other conductors to keep the current from leaking away.
INSPECTOR, RADIO.--A U. S. inspector whose business it is to issue both station and operators' licenses in the district of which he is in charge.
INTERFERENCE.--The crossing or superposing of two sets of electric waves of the same or slightly different lengths which tend to oppose each other. It is the untoward interference between electric waves from different stations that makes selective signaling so difficult a problem.
INTERMEDIATE WAVES.--SeeWaves.
IONIC TUBES.--SeeVacuum Tubes.
INTERNATIONAL CODE.--See Code, International.
JAMMING.--Waves that are of such length and strength that when they interfere with incoming waves they drown them out.
JOULE.--The energy spent in 1 second by a flow of 1 ampere in 1 ohm.
JOULE'S LAW.--The relation between the heat produced in seconds to the resistance of the circuit, to the current flowing in it.
KENOTRON.--The trade name of a vacuum tube rectifier made by theRadio Corporation of America.
KICK-BACK.--Oscillating currents that rise in voltage and tend to flow back through the circuit that is supplying the transmitter with low voltage current.
KICK-BACK PREVENTION.--SeePrevention, Kick-Back.
KILOWATT.--1,000 watts.
LAMBDA.--SeePages 301, 302.[Appendix: Useful Abbreviations].
LATTICE WOUND COILS.--SeeCoils, Inductance.
LIGHTNING SWITCH.--SeeSwitch, Lightning.
LINE RADIO COMMUNICATION.--SeeWired Wireless.
LINE RADIO TELEPHONY.--SeeTelephony, Line Radio.
LITZENDRAHT.--A conductor formed of a number of fine copper wires either twisted or braided together. It is used to reduce theskin effect.SeeResistance, High Frequency.
LOAD FLICKER.--The flickering of electric lights on lines that supply wireless transmitting sets due to variations of the voltage on opening and closing the key.
LOADING COIL.--SeeCoil, Loading.
LONG WAVES.--SeeWaves.
LOOP AERIAL.--SeeAerial, Loop.
LOOSE COUPLED CIRCUITS.--SeeCircuits, Loose Coupled.
LOUD SPEAKER.--A telephone receiver connected to a horn, or a specially made one, that reproduces the incoming signals, words or music loud enough to be heard by a room or an auditorium full of people, or by large crowds out-doors.
MAGNETIC POLES.--SeePoles, Magnetic.
MEGOHM.--One million ohms.
METER, AUDIBILITY.--An instrument for measuring the loudness of a signal by comparison with another signal. It consists of a pair of headphones and a variable resistance which have been calibrated.
MHO.--The unit of conductance. As conductance is the reciprocal of resistance it is measured by thereciprocal ohmormho.
MICA.--A transparent mineral having a high insulating value and which can be split into very thin sheets. It is largely used in making condensers both for transmitting and receiving sets.
MICROFARAD.--The millionth part of afarad.
MICROHENRY.--The millionth part of afarad.
MICROMICROFARAD.--The millionth part of amicrofarad.
MICROHM.--The millionth part of anohm.
MICROPHONE TRANSFORMER.--SeeTransformer, Microphone.
MICROPHONE TRANSMITTER.--SeeTransmitter, Microphone.
MILLI-AMMETER.--An ammeter that measures a current by the one-thousandth of an ampere.
MODULATION.--(1) Inflection or varying the voice. (2) Varying the amplitude of oscillations by means of the voice.
MODULATION, BUZZER.--The modulation of radio frequency oscillations by a buzzer which breaks up the sustained oscillations of a transmitter into audio frequency impulses.
MILLIHENRY.--The thousandth part of ahenry.
MODULATION, CHOPPER.--The modulation of radio frequency oscillations by a chopper which breaks up the sustained oscillations of a transmitter into audio frequency impulses.
MODULATION, GRID.--The scheme of modulating an oscillator tube by connecting the secondary of a transformer, the primary of which is connected with a battery and a microphone transmitter, in the grid lead.
MODULATION, OVER.--SeeBlub Blub.
MODULATION, PLATE.--Modulating the oscillations set up by a vacuum tube by varying the current impressed on the plate.
MODULATOR TUBE.--A vacuum tube used as a modulator.
MOTION, WAVE.--(1) The to and fro motion of water at sea. (2) Waves transmitted by, in and through the air, or sound waves. (3) Waves transmitted by, in and through theether,orelectromagnetic waves,orelectric wavesfor short.
MOTOR-GENERATOR.--A motor and a dynamo built to run at the same speed and mounted on a common base, the shafts being coupled together. In wireless it is used for changing commercial direct current into direct current of higher voltages for energizing the plate of a vacuum tube oscillator.
MULTI-STAGE AMPLIFIERS.--SeeAmplifiers, Multi-Stage.
MUTUAL INDUCTION.--SeeInduction, Mutual.
MUSH.--Irregular intermediate frequencies set up by arc transmitters which interfere with the fundamental wave lengths.
MUSHY NOTE.--A note that is not clear cut, and hence hard to read, which is received by theheterodyne methodwhen damped waves or modulated continuous waves are being received.
NATIONAL ELECTRIC CODE.--SeeCode, National Electric.
NATIONAL ELECTRIC SAFETY CODE.--SeeCode, National Electric Safety.
NEGATIVE ELECTRICITY.--SeeElectricity, Negative.
NON-SYNCHRONOUS GAP.--SeeGap, Non-Synchronous.
OHM.--The resistance of a thread of mercury at the temperature of melting ice, 14.4521 grams in mass, of uniform cross-section and a length of 106.300 centimeters.
OHM'S LAW.--The important fixed relation between the electric current, its electromotive force and the resistance of the conductor in which it flows.
OPEN CIRCUIT.--SeeCircuit, Open.
OPEN CORE TRANSFORMER.--SeeTransformer, Open Core.
OSCILLATION TRANSFORMER.--SeeTransformer, Oscillation.
OSCILLATIONS, ELECTRIC.--A current of high frequency that surges through an open or a closed circuit. (1) Electric oscillations may be set up by a spark gap, electric arc or a vacuum tube, when they have not only a high frequency but a high potential, or voltage. (2) When electric waves impinge on an aerial wire they are transformed into electric oscillations of a frequency equal to those which emitted the waves, but since a very small amount of energy is received their potential or voltage is likewise very small.
OSCILLATION TRANSFORMER.--SeeTransformer.
OSCILLATION VALVE.--SeeVacuum Tube.
OSCILLATOR TUBE.--A vacuum tube which is used to produce electric oscillations.
OVER MODULATION.--SeeBlub Blub.
PANCAKE OSCILLATION TRANSFORMER.--Disk-shaped coils that are used for receiving tuning inductances.
PERMEABILITY, MAGNETIC.--The degree to which a substance can be magnetized. Iron has a greater magnetic permeability than air.
PHASE.--A characteristic aspect or appearance that takes place at the same point or part of a cycle.
PICK-UP CIRCUITS.--SeeCircuits, Stand-by.
PLATE CIRCUIT REACTOR.--SeeReactor, Plate Circuit.
PLATE CURRENT.--SeeCurrent, Plate.
PLATE MODULATION.--SeeModulation, Plate.
PLATE VOLTAGE.--SeeFoliage, Plate.
POLES, BATTERY.--The positive and negative terminals of the elements of a battery. On a storage battery these poles are marked + and - respectively.
POLES, MAGNETIC.--The ends of a magnet.
POSITIVE ELECTRICITY.--SeeElectricity, Positive.
POTENTIAL DIFFERENCE.--The electric pressure between two charged conductors or surfaces.
POTENTIOMETER.--A variable resistance used for subdividing the voltage of a current. Avoltage divider.
POWER TRANSFORMER.--SeeTransformer, Power.
POWER TUBE.--SeeGenerator Tube.
PRIMARY BATTERY.--SeeBattery, Primary.
PREVENTION, KICK-BACK.--A choke coil placed in the power circuit to prevent the high frequency currents from getting into the transformer and breaking down the insulation.
Q S T.--An abbreviation used in wireless communication for (1) the question "Have you received the general call?" and (2) the notice, "General call to all stations."
QUENCHED GAP.--SeeGap, Quenched.
RADIATION.--The emission, or throwing off, of electric waves by an aerial wire system.
RADIO AMMETER.--SeeAmmeter, Hot Wire.
RADIO FREQUENCY.--SeeFrequency, Radio.
RADIO FREQUENCY AMPLIFICATION.--SeeAmplification, Radio Frequency.
RADIO FREQUENCY CURRENT.--SeeCurrent, Radio Frequency.
RADIO INSPECTOR.--SeeInspector, Radio.
RADIOTRON.--The trade name of vacuum tube detectors, amplifiers, oscillators and modulators made by theRadio Corporation of America.
RADIO WAVES.--SeeWaves, Radio.
REACTANCE.--When a circuit has inductance and the current changes in value, it is opposed by the voltage induced by the variation of the current.
REACTANCE, CAPACITY.--The capacity reactance is the opposition offered to a current by a capacity. It is measured as a resistance, that is, inohms.
RECEIVING TUNING COILS.--SeeCoils, Inductance.
RECEIVER, LOUD SPEAKING.--SeeLoud Speakers.
RECEIVER, WATCH CASE.--A compact telephone receiver used for wireless reception.
REACTANCE, INDUCTIVE.--The inductive reactance is the opposition offered to the current by an inductance coil. It is measured as a resistance, that is, inohms.
REACTOR, FILTER.--A reactance coil for smoothing out the pulsating direct currents as they come from the rectifier.
REACTOR, PLATE CIRCUIT.--A reactance coil used in the plate circuit of a wireless telephone to keep the direct current supply at a constant voltage.
RECEIVER.--(1) A telephone receiver. (2) An apparatus for receiving signals, speech or music. (3) Better called areceptorto distinguish it from a telephone receiver.
RECTIFIER.--(1) An apparatus for changing alternating current into pulsating direct current. (2) Specifically in wireless (a) a crystal or vacuum tube detector, and (b) a two-electrode vacuum tube used for changing commercial alternating current into direct current for wireless telephony.
REGENERATIVE AMPLIFICATION.--SeeAmplification, Regenerative.
RECEPTOR.--A receiving set.
RECEPTOR, AUTODYNE.--A receptor that has a regenerative circuit and the same tube is used as a detector and as a generator of local oscillations.
RECEPTOR, BEAT.--A heterodyne receptor.
RECEPTOR, HETERODYNE.--A receiving set that uses a separate vacuum tube to set up the second series of waves for beat reception.
REGENERATIVE ACTION.--SeeFeed-Back Action.
REGENERATIVE AMPLIFICATION.--SeeAmplification, Regenerative.
RELAY, ELECTRON.--A vacuum tube when used as a detector or an amplifier.
REPEATING COIL.--A transformer used in connecting up a wireless receiver with a wire transmitter.
RESISTANCE.--The opposition offered by a wire or other conductor to the passage of a current.
RESISTANCE, AERIAL.--The resistance of the aerial wire to oscillating currents. This is greater than its ordinary ohmic resistance due to the skin effect. SeeResistance, High Frequency.
RESISTANCE BOX.--SeeResistor.
RESISTANCE COUPLING.--SeeCoupling, Resistance.
RESISTANCE, HIGH FREQUENCY.--When a high frequency current oscillates on a wire two things take place that are different than when a direct or alternating current flows through it, and these are (1) the current inside of the wire lags behind that of the current on the surface, and (2) the amplitude of the current is largest on the surface and grows smaller as the center of the wire is reached. This uneven distribution of the current is known as theskin effectand it amounts to the same thing as reducing the size of the wire, hence the resistance is increased.
RESISTIVITY.--The resistance of a given length of wire of uniform cross section. The reciprocal ofconductivity.
RESISTOR.--A fixed or variable resistance unit or a group of such units. Variable resistors are also calledresistance boxesand more oftenrheostats.
RESONANCE.--(1) Simple resonance of sound is its increase set up by one body by the sympathetic vibration of a second body. (2) By extension the increase in the amplitude of electric oscillations when the circuit in which they surge has anaturalperiod that is the same, or nearly the same, as the period of the first oscillation circuit.
RHEOSTAT.--A variable resistance unit. SeeResistor.
RHEOSTAT, CARBON.--A carbon rod, or carbon plates or blocks, when used as variable resistances.
RHEOSTAT, FILAMENT.--A variable resistance used for keeping the current of the storage battery which heats the filament of a vacuum tube at a constant voltage.
ROTATING COIL.--SeeCoil.
ROTARY GAP.--SeeGap.
ROTOR.--The rotating coil of a variometer or a variocoupler.
RUHMKORFF COIL.--SeeCoil, Induction.
SATURATION.--The maximum plate current that a vacuum tube will take.
SENSITIVE SPOTS.--Spots on detector crystals that are sensitive to the action of electric oscillations.
SHORT WAVES.--SeeWaves.
SIDE WAVES.--SeeWave Length Band.
SIGNALS, CONVENTIONAL.--(1) The International Morse alphabet and numeral code, punctuation marks, and a few important abbreviations used in wireless telegraphy. (2) Dot and dash signals for distress call, invitation to transmit, etc. Now used for all general public service wireless communication.
SKIN EFFECT.--SeeResistance, High Frequency.
SOFT TUBE.--A vacuum tube in which the vacuum is low, that is, it is not highly exhausted.
SPACE CHARGE EFFECT.--The electric field intensity due to the pressure of the negative electrons in the space between the filament and plate which at last equals and neutralizes that due to the positive potential of the plate so that there is no force acting on the electrons near the filament.
SPARK.--SeeDischarge.
SPARK COIL.--SeeCoil, Induction.
SPARK DISCHARGE.--SeeSpark, Electric.
SPARK FREQUENCY.--SeeFrequency, Spark.
SPARK GAP.--(1) Aspark gap,without the hyphen, means the apparatus in which sparks take place; it is also called aspark discharger.(2)Spark-gap,with the hyphen, means the air-gap between the opposed faces of the electrodes in which sparks are produced.
SPIDER WEB INDUCTANCE COIL.--SeeCoil, Spider Web Inductance.
SPREADER.--A stick of wood, or spar, that holds the wires of the aerial apart.
STAGGER WOUND COILS.--SeeCoils, Inductance.
STAND-BY CIRCUITS.--SeeCircuits, Stand-By.
STATIC.--Also calledatmospherics, grinders, strays, X's,and, when bad enough, by other names. It is an electrical disturbance in the atmosphere which makes noises in the telephone receiver.
STATOR.--The fixed or stationary coil of a variometer or a variocoupler.
STORAGE BATTERY.--SeeBattery, Storage.
STRAY ELIMINATION.--A method for increasing the strength of the signals as against the strength of the strays. SeeStatic.
STRAYS.--SeeStatic.
STRANDED WIRE.--SeeWire, Stranded.
SUPER-HETERODYNE RECEPTOR.--SeeHeterodyne, Super.
SWINGING.--SeeFading.
SWITCH, AERIAL.--A switch used to change over from the sending to the receiving set, and the other way about, and connect them with the aerial.
SWITCH, LIGHTNING.--The switch that connects the aerial with the outside ground when the apparatus is not in use.
SYMBOLS, APPARATUS.--Also calledconventional symbols. These are diagrammatic lines representing various parts of apparatus so that when a wiring diagram of a transmitter or a receptor is to be made it is only necessary to connect them together. They are easy to make and easy to read. SeePage 307[Appendix: Symbols Used for Apparatus].
SYNCHRONOUS GAP.--SeeGap, Synchronous.
TELEPHONY, LINE RADIO.--SeeWired Wireless.
THERMAL AMMETER.--SeeAmmeter, Hot Wire.
THREE ELECTRODE VACUUM TUBE.--See Vacuum Tube, Three Electrode.
TIKKER.--A slipping contact device that breaks up the sustained oscillations at the receiving end into groups so that the signals can be heard in the head phones. The device usually consists of a fine steel or gold wire slipping in the smooth groove of a rotating brass wheel.
TRANSFORMER.--A primary and a secondary coil for stepping up or down a primary alternating or oscillating current.
TRANSMITTER, MICROPHONE.--A telephone transmitter of the kind that is used in the Bell telephone system.
TRANSMITTING TUNING COILS.--SeeCoils, Inductance.
TUNING.--When the open and closed oscillation circuits of a transmitter or a receptor are adjusted so that both of the former will permit electric oscillations to surge through them with the same frequency, they are said to be tuned. Likewise, when the sending and receiving stations are adjusted to the same wave length they are said to betuned.
TUNING COILS.--SeeCoils, Inductance.
TWO ELECTRODE VACUUM TUBE.--SeeVacuum Tube, Two Electrode.
VACUUM TUBE.--A tube with two or three electrodes from which the air has been exhausted, or which is filled with an inert gas, and used as a detector, an amplifier, an oscillator or a modulator in wireless telegraphy and telephony.
VALVE.--SeeVacuum Tube.
VALVE, FLEMING.--SeeFleming Valve.
VARIABLE CONDENSER.--SeeCondenser, Variable.
VARIABLE INDUCTANCE.--SeeInductance, Variable.
VARIABLE RESISTANCE.--SeeResistance, Variable.
VARIOCOUPLER.--A tuning device for varying the inductance of the receiving oscillation circuits. It consists of a fixed and a rotatable coil whose windings are not connected with each other.
VARIOMETER.--A tuning device for varying the inductance of the receiving oscillation currents. It consists of a fixed and a rotatable coil with the coils connected in series.
VERNIER CONDENSER.--SeeCondenser, Vernier.
VOLT.--The electromotive force which produces a current of 1 ampere when steadily applied to a conductor the resistance of which is one ohm.
VOLTAGE DIVIDER.--SeePotentiometer.
VOLTAGE, PLATE.--The voltage of the current that is used to energize the plate of a vacuum tube.
VOLTMETER.--An instrument for measuring the voltage of an electric current.
WATCH CASE RECEIVER.--SeeReceiver, Watch Case.
WATER-PIPE GROUND.--SeeGround, Water-Pipe.
WATT.--The power spent by a current of 1 ampere in a resistance of 1 ohm.
WAVE, BROAD.--A wave having a high decrement, when the strength of the signals is nearly the same over a wide range of wave lengths.
WAVE LENGTH.--Every wave of whatever kind has a length. The wave length is usually taken to mean the distance between the crests of two successive waves.
WAVE LENGTH BAND.--In wireless reception when continuous waves are being sent out and these are modulated by a microphone transmitter the different audio frequencies set up corresponding radio frequencies and the energy of these are emitted by the aerial; this results in waves of different lengths, or a band of waves as it is called.
WAVE METER.--An apparatus for measuring the lengths of electric waves set up in the oscillation circuits of sending and receiving sets.
WAVE MOTION.--Disturbances set up in the surrounding medium as water waves in and on the water, sound waves in the air and electric waves in the ether.
WAVES.--SeeWave Motion.
WAVES, ELECTRIC.--Electromagnetic waves set up in and transmitted by and through the ether.
WIRELESS TELEGRAPH CODE.--SeeCode, International.
WIRE, ENAMELLED.--Wire that is given a thin coat of enamel which insulates it.
WIRE, PHOSPHOR BRONZE.--A very strong wire made of an alloy of copper and containing a trace of phosphorus.
WIRED WIRELESS.--Continuous waves of high frequency that are sent over telephone wires instead of through space. Also calledline radio communication; carrier frequency telephony, carrier current telephony; guided wave telephonyandwired wireless.
X'S.--SeeStatic.
ZINCITE.--SeeDetector.
Don'tuse iron wire for your aerial.
Don'tfail to insulate it well at both ends.
Don'thave it longer than 75 feet for sending out a 200-meter wave.
Don'tfail to use a lightning arrester, or better, a lightning switch, for your receiving set.
Don'tfail to use a lightning switch with your transmitting set.
Don'tforget you must have an outside ground.
Don'tfail to have the resistance of your aerial as small as possible. Use stranded wire.
Don'tfail to solder the leading-in wire to the aerial.
Don'tfail to properly insulate the leading-in wire where it goes through the window or wall.
Don'tlet your aerial or leading-in wire touch trees or other objects.
Don'tlet your aerial come too close to overhead wires of any kind.
Don'trun your aerial directly under, or over, or parallel with electric light or other wires.
Don'tfail to make a good ground connection with the water pipe inside.
Don'tattempt to send until you get your license.
Don'tfail to live up to every rule and regulation.
Don'tuse an input of more than 1/2 a kilowatt if you live within 5 nautical miles of a naval station.
Don'tsend on more than a 200-meter wave if you have a restricted or general amateur license.
Don'tuse spark gap electrodes that are too small or they will get hot.
Don'tuse too long or too short a spark gap. The right length can be found by trying it out.
Don'tfail to use a safety spark gap between the grid and the filament terminals where the plate potential is above 2,000 volts.
Don'tbuy a motor-generator set if you have commercial alternating current in your home.
Don'toverload an oscillation vacuum tube as it will greatly shorten its life. Use two in parallel.
Don'toperate a transmitting set without a hot-wire ammeter in the aerial.
Don'tuse solid wire for connecting up the parts of transmitters. Use stranded or braided wire.
Don'tfail to solder each connection.
Don'tuse soldering fluid, use rosin.
Don'tthink that all of the energy of an oscillation tube cannot be used for wave lengths of 200 meters and under. It can be if the transmitting set and aerial are properly designed.
Don'trun the wires of oscillation circuits too close together.
Don'tcross the wires of oscillation circuits except at right angles.
Don'tset the transformer of a transmitting set nearer than 3 feet to the condenser and tuning coil.
Don'tuse a rotary gap in which the wheel runs out of true.
Don'texpect to get as good results with a crystal detector as with a vacuum tube detector.
Don'tbe discouraged if you fail to hit the sensitive spot of a crystal detector the first time--or several times thereafter.
Don'tuse a wire larger thanNo. 80for the wire electrode of a crystal detector.
Don'ttry to use a loud speaker with a crystal detector receiving set.
Don'texpect a loop aerial to give worthwhile results with a crystal detector.
Don'thandle crystals with your fingers as this destroys their sensitivity. Use tweezers or a cloth.
Don'timbed the crystal in solder as the heat destroys its sensitivity. UseWood's metal,or some other alloy which melts at or near the temperature of boiling water.
Don'tforget that strong static and strong signals sometimes destroy the sensitivity of crystals.
Don'theat the filament of a vacuum tube to greater brilliancy than is necessary to secure the sensitiveness required.
Don'tuse a plate voltage that is less or more than it is rated for.
Don'tconnect the filament to a lighting circuit.
Don'tuse dry cells for heating the filament except in a pinch.
Don'tuse a constant current to heat the filament, use a constant voltage.
Don'tuse a vacuum tube in a horizontal position unless it is made to be so used.
Don'tfail to properly insulate the grid and plate leads.
Don'tuse more than 1/3 of the rated voltage on the filament and on the plate when trying it out for the first time.
Don'tfail to use alternating current for heating the filament where this is possible.
Don'tfail to use a voltmeter to find the proper temperature of the filament.
Don'texpect to get results with a loud speaker when using a single vacuum tube.
Don'tfail to protect your vacuum tubes from mechanical shocks and vibration.
Don'tfail to cut off theAbattery entirely from the filament when you are through receiving.
Don'tswitch on theAbattery current all at once through the filament when you start to receive.
Don'texpect to get the best results with a gas-content detector tube without using a potentiometer.
Don'tconnect a potentiometer across theBbattery or it will speedily run down.
Don'texpect to get as good results with a single coil tuner as you would with a loose coupler.
Don'texpect to get as good results with a two-coil tuner as with one having a third, ortickler, coil.
Don'tthink you have to use a regenerative circuit, that is, one with a tickler coil, to receive with a vacuum tube detector.
Don'tthink you are the only amateur who is troubled with static.
Don'texpect to eliminate interference if the amateurs around you are sending with spark sets.
Don'tlay out or assemble your set on a panel first. Connect it up on a board and find out if everything is right.
Don'ttry to connect up your set without a wiring diagram in front of you.
Don'tfail to shield radio frequency amplifiers.
Don'tset the axes of the cores of radio frequency transformers in a line. Set them at right angles to each other.
Don'tuse wire smaller thanNo. 14for connecting up the various parts.
Don'tfail to adjust theBbattery after putting in a fresh vacuum tube, as its sensitivity depends largely on the voltage.
Don'tfail to properly space the parts where you use variometers.
Don'tfail to put a copper shield between the variometer and the variocoupler.
Don'tfail to keep the leads to the vacuum tube as short as possible.
Don'tthrow your receiving set out of the window if ithowls. Try placing the audio-frequency transformers farther apart and the cores of them at right angles to each other.
Don'tuse condensers with paper dielectrics for an amplifier receiving set or it will be noisy.
Don'texpect as good results with a loop aerial, or when? using the bed springs, as an out-door aerial will give you.
Don'tuse an amplifier having a plate potential of less than 100 volts for the last step where a loud speaker is to be used.
Don'ttry to assemble a set if you don't know the difference between a binding post and a blue print. Buy a set ready to use.
Don'texpect to get Arlington time signals and the big cableless stations if your receiver is made for short wave lengths.
Don'ttake your headphones apart. You are just as apt to spoil them as you would a watch.
Don'texpect to get results with a Bell telephone receiver.
Don'tforget that there are other operators using the ether besides yourself.
Don'tlet yourBbattery get damp and don't let it freeze.
Don'ttry to recharge yourBbattery unless it is constructed for the purpose.
Don'tconnect a source of alternating current direct to your storage battery. You have to use a rectifier.
Don'tconnect the positive lead of the charging circuit with the negative terminal of your storage battery.
Don'tlet the electrolyte get lower than the tops of the plates of your storage battery.
Don'tfail to look after the condition of your storage battery once in a while.
Don'tbuy a storage battery that gives less than 6 volts for heating the filament.
Don'tfail to keep the specific gravity of the electrolyte of your storage battery between 1.225 and 1.300 Baume. This you can do with a hydrometer.
Don'tfail to recharge your storage battery when the hydrometer shows that the specific gravity of the electrolyte is close to 1.225.
Don'tkeep charging the battery after the hydrometer shows that the specific gravity is 1.285.
Don'tlet the storage battery freeze.
Don'tlet it stand for longer than a month without using unless you charge it.
Don'tmonkey with the storage battery except to add a little sulphuric acid to the electrolyte from time to time. If anything goes wrong with it better take it to a service station and let the expert do it.
Don'tthink you have an up-to-date transmitting station unless you are using C.W.
Don'tuse a wire from your lightning switch down to the outside ground that is smaller than No.4.
Don'ttry to operate your spark coil with 110-volt direct lighting current without connecting in a rheostat.
Don'ttry to operate your spark coil with 110-volt alternating lighting current without connecting in an electrolytic interrupter.
Don'ttry to operate an alternating current power transformer with 110-volt direct current without connecting in an electrolytic interruptor.
Don't--no never--connect one side of the spark gap to the aerial wire and the other side of the spark gap to the ground. The Government won't have it--that's all.
Don'ttry to tune your transmitter to send out waves of given length by guesswork. Use a wavemeter.
Don'tusehard fiberfor panels. It is a very poor insulator where high frequency currents are used.
Don'tthink you are the only one who doesn't know all about wireless. Wireless is a very complex art and there are many things that those experienced have still to learn.