Connecticut Telephone and Telegraph Co., Meriden, Conn.
Continental Fiber Co., Newark, Del.
Coto-Coil Co., Providence, R. I.
Crosley Mfg. Co., Cincinnati, Ohio.
Doolittle (F. M.), 817 Chapel St., New Haven, Conn.
Edelman (Philip E.), 9 Cortlandt St., New York City.
Edison Storage Battery Co., Orange, N. J.
Electric Specialty Co., Stamford, Conn.
Electrose Mfg. Co., 60 Washington St., Brooklyn, N. Y.
General Electric Co., Schenectady, N. Y.
Grebe (A. H.) and Co., Inc., Richmond Hill, N. Y. C.
International Brass and Electric Co., 176 Beekman St., New York City.
International Insulating Co., 25 West 45th St., New York City.
King Amplitone Co., 82 Church St., New York City.
Kennedy (Colin B.) Co., Rialto Bldg., San Francisco, Cal.
Magnavox Co., Oakland, Cal.
Manhattan Electrical Supply Co., Park Place, N. Y.
Marshall-Gerken Co., Toledo, Ohio.
Michigan Paper Tube and Can Co., 2536 Grand River Ave., Detroit, Mich.
Murdock (Wm. J.) Co., Chelsea, Mass.
National Carbon Co., Inc., Long Island City, N. Y.
Pittsburgh Radio and Appliance Co., 112 Diamond St., Pittsburgh, Pa,
Radio Corporation of America, 233 Broadway, New York City.
Riley-Klotz Mfg. Co., 17-19 Mulberry St., Newark, N. J.
Radio Specialty Co., 96 Park Place, New York City.
Roller-Smith Co., 15 Barclay St., New York City.
Tuska (C. D.) Co., Hartford, Conn.
Western Electric Co., Chicago, Ill.
Westinghouse Electric Co., Pittsburgh, Pa.
Weston Electrical Instrument Co., 173 Weston Ave., Newark, N. J.
Westfield Machine Co., Westfield, Mass.
ABBREVIATIONS OF COMMON TERMS
A. ..............Aerial
A.C. ............Alternating Current
A.F. ............Audio Frequency
B. and S. .......Brown & Sharpe Wire Gauge
C. ..............Capacity or Capacitance
C.G.S. ..........Centimeter-Grain-Second
Cond. ...........Condenser
Coup. ...........Coupler
C.W. ............Continuous Waves
D.C. ............Direct Current
D.P.D.T. ........Double Point Double Throw
D.P.S.T. ........Double Point Single Throw
D.X. ............Distance
E. ..............Short for Electromotive Force (Volt)
E.M.F. ..........Electromotive Force
F. ..............Filament or Frequency
G. ..............Grid
Gnd. ............Ground
I. ..............Current Strength (Ampere)
I.C.W. ..........Interrupted Continuous Waves
KW. .............Kilowatt
L. ..............Inductance
L.C. ............Loose Coupler
Litz. ...........Litzendraht
Mfd. ............Microfarad
Neg. ............Negative
O.T. ............Oscillation Transformer
P. ..............Plate
Prim. ...........Primary
Pos. ............Positive
R. ..............Resistance
R.F. ............Radio Frequency
Sec. ............Secondary
S.P.D.T. ........Single Point Double Throw
S.P.S.T. ........Single Point Single Throw
S.R. ............Self Rectifying
T. ..............Telephone or Period (time) of Complete
Oscillation
Tick. ...........Tickler
V. ..............Potential Difference
Var. ............Variometer
Var. Cond. ......Variable Condenser
V.T. ............Vacuum Tube
W.L. ............Wave Length
X. ..............Reactance
GLOSSARY
A BATTERY.--See Battery A.
ABBREVIATIONS, CODE.--Abbreviations of questions and answers used in
wireless communication. The abbreviation _of a question_ is usually in
three letters of which the first is Q. Thus Q R B is the code
abbreviation of "_what is your distance?_" and the answer "_My
distance is_..." See Page 306 [Appendix: List of Abbreviations].
ABBREVIATIONS, UNITS.--Abbreviations of various units used in wireless
electricity. These abbreviations are usually lower case letters of the
Roman alphabet, but occasionally Greek letters are used and other
signs. Thus _amperes_ is abbreviated _amp., micro_, which means _one
millionth_, [Greek: mu], etc. See Page 301 [Appendix: Useful
Abbreviations].
ABBREVIATIONS OF WORDS AND TERMS.--Letters used instead of words and
terms for shortening them up where there is a constant repetition of
them, as _A.C._ for _alternating current; C.W._ for _continuous waves;
V.T._ for _vacuum tube_, etc. See Page 312 [Appendix: Abbreviations of
Common Terms].
AERIAL.--Also called _antenna_. An aerial wire. One or more wires
suspended in the air and insulated from its supports. It is the aerial
that sends out the waves and receives them.
AERIAL, AMATEUR.--An aerial suitable for sending out 200 meter wave
lengths. Such an aerial wire system must not exceed 120 feet in length
from the ground up to the aerial switch and from this through the
leading-in wire to the end of the aerial.
AERIAL AMMETER.--See _Ammeter, Hot Wire_.
AERIAL, BED-SPRINGS.--Where an outdoor aerial is not practicable
_bed-springs_ are often made to serve the purpose.
AERIAL CAPACITY.--See _Capacity, Aerial._
AERIAL COUNTERPOISE.--Where it is not possible to get a good ground an
_aerial counterpoise_ or _earth capacity_ can be used to advantage.
The counterpoise is made like the aerial and is supported directly
under it close to the ground but insulated from it.
AERIAL, DIRECTIONAL.--A flat-top or other aerial that will transmit
and receive over greater distances to and from one direction than to
and from another.
AERIAL, GROUND.--Signals can be received on a single long wire when it
is placed on or buried in the earth or immersed in water. It is also
called a _ground antenna_ and an _underground aerial._
AERIAL, LOOP.--Also called a _coil aerial, coil antenna, loop aerial,
loop antenna_ and when used for the purpose a _direction finder_. A
coil of wire wound on a vertical frame.
AERIAL RESISTANCE.--See _Resistance, Aerial._
AERIAL SWITCH.--See _Switch Aerial._
AERIAL WIRE.--(1) A wire or wires that form the aerial. (2) Wire that
is used for aerials; this is usually copper or copper alloy.
AERIAL WIRE SYSTEM.--An aerial and ground wire and that part of the
inductance coil which connects them. The open oscillation circuit of
a sending or a receiving station.
AIR CORE TRANSFORMER.--See _Transformer, Air Core._
AMATEUR AERIAL OR ANTENNA.--See _Aerial, Amateur._
ALTERNATOR.--An electric machine that generates alternating current.
ALPHABET, INTERNATIONAL CODE.--A modified Morse alphabet of dots and
dashes originally used in Continental Europe and, hence, called the
_Continental Code_. It is now used for all general public service
wireless communication all over the world and, hence, it is called the
_International Code_. See page 305 [Appendix: International Morse
Code].
ALTERNATING CURRENT (_A.C._)--See _Current._
ALTERNATING CURRENT TRANSFORMER.--See _Transformer_.
AMATEUR GROUND.--See _Ground, Amateur_.
AMMETER.--An instrument used for measuring the current strength, in
terms of amperes, that flows in a circuit. Ammeters used for measuring
direct and alternating currents make use of the _magnetic effects_ of
the currents. High frequency currents make use of the _heating
effects_ of the currents.
AMMETER, HOT-WIRE.--High frequency currents are usually measured by
means of an instrument which depends on heating a wire or metal strip
by the oscillations. Such an instrument is often called a _thermal
ammeter_, _radio ammeter_ and _aerial ammeter_.
AMMETER, AERIAL.--See _Ammeter, Hot Wire_.
AMMETER, RADIO.--See _Ammeter, Hot Wire_.
AMPERE.--The current which when passed through a solution of nitrate
of silver in water according to certain specifications, deposits
silver at the rate of 0.00111800 of a gram per second.
AMPERE-HOUR.--The quantity of electricity transferred by a current of
1 ampere in 1 hour and is, therefore, equal to 3600 coulombs.
AMPERE-TURNS.--When a coil is wound up with a number of turns of wire
and a current is made to flow through it, it behaves like a magnet. B
The strength of the magnetic field inside of the coil depends on (1)
the strength of the current and (2) the number of turns of wire on the
coil. Thus a feeble current flowing through a large number of turns
will produce as strong a magnetic field as a strong current flowing
through a few turns of wire. This product of the current in amperes
times the number of turns of wire on the coil is called the
_ampere-turns_.
AMPLIFICATION, AUDIO FREQUENCY.--A current of audio frequency that is
amplified by an amplifier tube or other means.
AMPLIFICATION, CASCADE.--See _Cascade Amplification_.
AMPLIFICATION, RADIO FREQUENCY.--A current of radio frequency that is
amplified by an amplifier tube or other means before it reaches the
detector.
AMPLIFICATION, REGENERATIVE.--A scheme that uses a third circuit to
feed back part of the oscillations through a vacuum tube and which
increases its sensitiveness when used as a detector and multiplies its
action as an amplifier and an oscillator.
AMPLIFIER, AUDIO FREQUENCY.--A vacuum tube or other device that
amplifies the signals after passing through the detector.
AMPLIFIER, MAGNETIC.--A device used for controlling radio frequency
currents either by means of a telegraph key or a microphone
transmitter. The controlling current flows through a separate circuit
from that of the radio current and a fraction of an ampere will
control several amperes in the aerial wire.
AMPLIFIERS, MULTI-STAGE.--A receiving set using two or more
amplifiers. Also called _cascade amplification_.
AMPLIFIER, VACUUM TUBE.--A vacuum tube that is used either to amplify
the radio frequency currents or the audio frequency currents.
AMPLITUDE OF WAVE.--The greatest distance that a point moves from its
position of rest.
AMPLIFYING TRANSFORMER, AUDIO.--See _Transformer, Audio Amplifying_.
AMPLIFYING MODULATOR VACUUM TUBE.--See _Vacuum Tube, Amplifying
Modulator_.
AMPLIFYING TRANSFORMER RADIO.--See _Transformer, Radio Amplifying_.
ANTENNA, AMATEUR.--See _Aerial, Amateur_.
ANTENNA SWITCH.--See _Switch, Aerial_.
APPARATUS SYMBOLS.--See _Symbols, Apparatus_.
ARMSTRONG CIRCUIT.--See _Circuit, Armstrong_.
ATMOSPHERICS.--Same as _Static_, which see.
ATTENUATION.--In Sending wireless telegraph and telephone messages the
amplitude of the electric waves is damped out as the distance
increases. This is called _attenuation_ and it increases as the
frequency is increased. This is the reason why short wave lengths
will not carry as far as long wave lengths.
AUDIO FREQUENCY AMPLIFIER.--See _Amplifier, Audio Frequency_.
AUDIO FREQUENCY AMPLIFICATION.--See _Amplification, Audio Frequency_.
AUDIBILITY METER.--See _Meter, Audibility_.
AUDIO FREQUENCY.--See _Frequency, Audio_.
AUDIO FREQUENCY CURRENT.--See _Current, Audio Frequency_.
AUDION.--An early trade name given to the vacuum tube detector.
AUTODYNE RECEPTOR.--See _Receptor, Autodyne_.
AUTO TRANSFORMER.--See _Transformer, Auto_.
BAKELITE.--A manufactured insulating compound.
B BATTERY.--See _Battery B_.
BAND, WAVE LENGTH.--See _Wave Length Band_.
BASKET WOUND COILS.--See _Coils, Inductance_.
BATTERY, A.--The 6-volt storage battery used to heat the filament of a
vacuum tube, detector or amplifier.
BATTERY, B.--The 22-1/2-volt dry cell battery used to energize the
plate of a vacuum tube detector or amplifier.
BATTERY, BOOSTER.--This is the battery that is connected in series
with the crystal detector.
BATTERY, C.--A small dry cell battery sometimes used to give the grid
of a vacuum tube detector a bias potential.
BATTERY, EDISON STORAGE.--A storage battery in which the elements are
made of nickel and iron and immersed in an alkaline
_electrolyte_.
BATTERY, LEAD STORAGE.--A storage battery in which the elements are
made of lead and immersed in an acid electrolyte.
BATTERY POLES.--See _Poles, Battery_.
BATTERY, PRIMARY.--A battery that generates current by chemical
action.
BATTERY, STORAGE.--A battery that develops a current after it has been
charged.
BEAT RECEPTION.--See _Heterodyne Reception_.
BED SPRINGS AERIAL.--See _Aerial, Bed Springs_.
BLUB BLUB.--Over modulation in wireless telephony.
BROAD WAVE.--See _Wave, Broad_.
BRUSH DISCHARGE.--See _Discharge_.
BUZZER MODULATION.--See _Modulation, Buzzer_.
BLUE GLOW DISCHARGE.--See _Discharge_.
BOOSTER BATTERY.--See _Battery, Booster_.
BROADCASTING.--Sending out intelligence and music from a central
station for the benefit of all who live within range of it and who
have receiving sets.
CAPACITANCE.--Also called by the older name of _capacity_. The
capacity of a condenser, inductance coil or other device capable of
retaining a charge of electricity. Capacitance is measured in terms
of the _microfarad_.
CAPACITIVE COUPLING.--See _Coupling, Capacitive_.
CAPACITY.--Any object that will retain a charge of electricity; hence
an aerial wire, a condenser or a metal plate is sometimes called a
_capacity_.
CAPACITY, AERIAL.--The amount to which an aerial wire system can be
charged. The _capacitance_ of a small amateur aerial is from
0.0002 to 0.0005 microfarad.
CAPACITY, DISTRIBUTED.--A coil of wire not only has inductance, but
also a certain small capacitance. Coils wound with their turns
parallel and having a number of layers have a _bunched capacitance_
which produces untoward effects in oscillation circuits. In honeycomb
and other stagger wound coils the capacitance is more evenly
distributed.
CAPACITY REACTANCE.--See _Reactance, Capacity_.
CAPACITY UNIT.--See _Farad_.
CARBON RHEOSTATS.--See _Rheostat, Carbon_.
CARBORUNDUM DETECTOR.--See _Detector_.
CARRIER CURRENT TELEPHONY.--See _Wired-Wireless_.
CARRIER FREQUENCY.--See _Frequency, Carrier_.
CARRIER FREQUENCY TELEPHONY.--See _Wired-Wireless_.
CASCADE AMPLIFICATION.--Two or more amplifying tubes hooked up in a
receiving set.
CAT WHISKER CONTACT.--A long, thin wire which makes contact with the
crystal of a detector.
CENTIMETER OF CAPACITANCE.--Equal to 1.11 _microfarads_.
CENTIMETER OF INDUCTANCE.--Equal to one one-thousandth part of a
_microhenry_.
CELLULAR COILS.--See _Coils, Inductance_.
C.G.S. ELECTROSTATIC UNIT OF CAPACITANCE.--See _Centimeter of
Capacitance_.
CHARACTERISTICS.--The special behavior of a device, such as an aerial,
a detector tube, etc.
CHARACTERISTICS, GRID.--See _Grid Characteristics_.
CHOKE COILS.--Coils that prevent the high voltage oscillations from
surging back into the transformer and breaking down the insulation.
CHOPPER MODULATION.--See _Modulation, Chopper_.
CIRCUIT.--Any electrical conductor through which a current can flow. A
low voltage current requires a loop of wire or other conductor both
ends of which are connected to the source of current before it can
flow. A high frequency current will surge in a wire which is open at
both ends like the aerial.
Closed Circuit.--A circuit that is continuous.
Open Circuit.--A conductor that is not continuous.
Coupled Circuits.--Open and closed circuits connected together
by inductance coils, condensers or resistances. See _coupling_.
Close Coupled Circuits.--Open and closed circuits connected
directly together with a single inductance coil.
Loose Coupled Circuits.--Opened and closed currents connected
together inductively by means of a transformer.
Stand-by Circuits.--Also called _pick-up_ circuits. When listening-in
for possible calls from a number of stations, a receiver is used which
will respond to a wide band of wave lengths.
Armstrong Circuits.--The regenerative circuit invented by Major E. H.
Armstrong.
CLOSE COUPLED CIRCUITS.--See _Currents, Close Coupled_.
CLOSED CIRCUIT.--See _Circuit, Closed_.
CLOSED CORE TRANSFORMER.--See _Transformer, Closed Core_.
CODE.--
Continental.--Same as _International_.
International.--On the continent of Europe land lines use the
_Continental Morse_ alphabetic code. This code has come to be used
throughout the world for wireless telegraphy and hence it is now
called the _International code_. It is given on Page 305. [Appendix:
International Morse Code].
Morse.--The code devised by Samuel F. B. Morse and which is used on
the land lines in the U. S.
National Electric.--A set of rules and requirements devised by the
_National Board of Fire Underwriters_ for the electrical installations
in buildings on which insurance companies carry risks. This code also
covers the requirements for wireless installations. A copy may be had
from the _National Board of Fire Underwriters_, New York City, or from
your insurance agent.
National Electric Safety.--The Bureau of Standards, Washington, D. C.,
have investigated the precautions which should be taken for the safe
operation of all electric equipment. A copy of the _Bureau of
Standards Handbook No. 3_ can be had for 40 cents from the
_Superintendent of Documents_.
COEFFICIENT OF COUPLING.--See _Coupling, Coefficient of_.
COIL AERIAL.--See _Aerial, Loop_.
COIL ANTENNA.--See _Aerial, Loop_.
COIL, INDUCTION.--An apparatus for changing low voltage direct
currents into high voltage, low frequency alternating currents. When
fitted with a spark gap the high voltage, low frequency currents are
converted into high voltage, high frequency currents. It is then also
called a _spark coil_ and a _Ruhmkorff coil_.
COIL, LOADING.--A coil connected in the aerial or closed oscillation
circuit so that longer wave lengths can be received.
COIL, REPEATING.--See _Repeating Coil_.
COIL, ROTATING.--One which rotates on a shaft instead of sliding as in
a _loose coupler_. The rotor of a _variometer_ or _variocoupler_ is a
_rotating coil_.
COILS, INDUCTANCE.--These are the tuning coils used for sending and
receiving sets. For sending sets they are formed of one and two coils,
a single sending coil is generally called a _tuning inductance coil_,
while a two-coil tuner is called an _oscillation transformer_.
Receiving tuning coils are made with a single layer, single coil, or a
pair of coils, when it is called an oscillation _transformer_. Some
tuning inductance coils have more than one layer, they are then called
_lattice wound_, _cellular_, _basket wound_, _honeycomb_,
_duo-lateral_, _stagger wound_, _spider-web_ and _slab_ coils.
COMMERCIAL FREQUENCY.--See _Frequency, Commercial_.
CONDENSER, AERIAL SERIES.--A condenser placed in the aerial wire
system to cut down the wave length.
CONDENSER, VERNIER.--A small variable condenser used for receiving
continuous waves where very sharp tuning is desired.
CONDENSER.--All conducting objects with their insulation form
capacities, but a _condenser_ is understood to mean two sheets or
plates of metal placed closely together but separated by some
insulating material.
Adjustable Condenser.--Where two or more condensers can be coupled
together by means of plugs, switches or other devices.
Aerial Condenser.--A condenser connected in the aerial.
Air Condenser.--Where air only separates the sheets of metal.
By-Pass Condenser.--A condenser connected in the transmitting currents
so that the high frequency currents cannot flow back through the power
circuit.
Filter Condenser.--A condenser of large capacitance used in
combination with a filter reactor for smoothing out the pulsating
direct currents as they come from the rectifier.
Fixed Condenser.--Where the plates are fixed relatively to one
another.
Grid Condenser.--A condenser connected in series with the grid lead.
Leyden Jar Condenser.--Where glass jars are used.
Mica Condenser.--Where mica is used.
Oil Condenser.--Where the plates are immersed in oil.
Paper Condenser.--Where paper is used as the insulating material.
Protective.--A condenser of large capacity connected across the low
voltage supply circuit of a transmitter to form a by-path of kick-back
oscillations.
Variable Condenser.--Where alternate plates can be moved and so made
to interleave more or less with a set of fixed plates.
Vernier.--A small condenser with a vernier on it so that it can be
very accurately varied. It is connected in parallel with the variable
condenser used in the primary circuit and is used for the reception of
continuous waves where sharp tuning is essential.
CONDENSITE.--A manufactured insulating compound.
CONDUCTIVITY.--The conductance of a given length of wire of uniform
cross section. The reciprocal of _resistivity_.
CONTACT DETECTORS.--See _Detectors, Contact_.
CONTINENTAL CODE.--See _Code, Continental_.
COULOMB.--The quantity of electricity transferred by a current of 1
ampere in 1 second.
CONVECTIVE DISCHARGE.--See _Discharge_.
CONVENTIONAL SIGNALS.--See _Signals, Conventional_.
COUNTER ELECTROMOTIVE FORCE.--See _Electromotive Force, Counter_.
COUNTERPOISE. A duplicate of the aerial wire that is raised a few feet
above the earth and insulated from it. Usually no connection is made
with the earth itself.
COUPLED CIRCUITS.--See _Circuit, Coupled_.
COUPLING.--When two oscillation circuits are connected together either
by the magnetic field of an inductance coil, or by the electrostatic
field of a condenser.
COUPLING, CAPACITIVE.--Oscillation circuits when connected together by
condensers instead of inductance coils.
COUPLING, COEFFICIENT OF.--The measure of the closeness of the
coupling between two coils.
COUPLING, INDUCTIVE.--Oscillation circuits when connected together by
inductance coils.
COUPLING, RESISTANCE.--Oscillation circuits connected together by a
resistance.
CRYSTAL RECTIFIER.--A crystal detector.
CURRENT, ALTERNATING (A.C.).--A low frequency current that surges to
and fro in a circuit.
CURRENT, AUDIO FREQUENCY.--A current whose frequency is low enough to
be heard in a telephone receiver. Such a current usually has a
frequency of between 200 and 2,000 cycles per second.
CURRENT, PLATE.--The current which flows between the filament and the
plate of a vacuum tube.
CURRENT, PULSATING.--A direct current whose voltage varies from moment
to moment.
CURRENT, RADIO FREQUENCY.--A current whose frequency is so high it
cannot be heard in a telephone receiver. Such a current may have a
frequency of from 20,000 to 10,000,000 per second.
CURRENTS, HIGH FREQUENCY.--(1) Currents that oscillate from 10,000 to
300,000,000 times per second. (2) Electric oscillations.
CURRENTS, HIGH POTENTIAL.--(1) Currents that have a potential of more
than 10,000 volts. (2) High voltage currents.
CYCLE.--(1) A series of changes which when completed are again at the
starting point. (2) A period of time at the end of which an
alternating or oscillating current repeats its original direction of
flow.
DAMPING.--The degree to which the energy of an electric oscillation is
reduced. In an open circuit the energy of an oscillation set up by a
spark gap is damped out in a few swings, while in a closed circuit it
is greatly prolonged, the current oscillating 20 times or more before
the energy is dissipated by the sum of the resistances of the circuit.
DECREMENT.--The act or process of gradually becoming less.
DETECTOR.--Any device that will (1) change the oscillations set up by
the incoming waves into direct current, that is which will rectify
them, or (2) that will act as a relay.
Carborundum.--One that uses a _carborundum_ crystal for the sensitive
element. Carborundum is a crystalline silicon carbide formed in the
electric furnace.
Cat Whisker Contact.--See _Cat Whisker Contact_.
Chalcopyrite.--Copper pyrites. A brass colored mineral used as a
crystal for detectors. See _Zincite_.
Contact.--A crystal detector. Any kind of a detector in which two
dissimilar but suitable solids make contact.
Ferron.--A detector in which iron pyrites are used as the sensitive
element.
Galena.--A detector that uses a galena crystal for the rectifying
element.
Iron Pyrites.--A detector that uses a crystal of iron pyrites for its
sensitive element.
Molybdenite.--A detector that uses a crystal of _sulphide of
molybdenum_ for the sensitive element.
Perikon.--A detector in which a _bornite_ crystal makes contact with a
_zincite_ crystal.
Silicon.--A detector that uses a crystal of silicon for its sensitive
element.
Vacuum Tube.--A vacuum tube (which see) used as a detector.
Zincite.--A detector in which a crystal of _zincite_ is used as the
sensitive element.
DE TUNING.--A method of signaling by sustained oscillations in which
the key when pressed down cuts out either some of the inductance or
some of the capacity and hence greatly changes the wave length.
DIELECTRIC.--An insulating material between two electrically charged
plates in which there is set up an _electric strain_, or displacement.
DIELECTRIC STRAIN.--The electric displacement in a dielectric.
DIRECTIONAL AERIAL.--See _Aerial, Directional_.
DIRECTION FINDER.--See _Aerial, Loop_.
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 a _brush discharge_. (2) A continuous
discharge between the terminals of a high potential apparatus is
termed a _convective discharge_. (3) The sudden breaking-down of the
air between the balls forming the spark gap is termed a _disruptive
discharge_; also called an _electric spark_, or just _spark_ for
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 a _blue glow
discharge_.
DISRUPTIVE DISCHARGE.--See _Discharge_.
DISTRESS CALL. [Morse code:] ...---... (SOS).
DISTRIBUTED CAPACITY.--See _Capacity, 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.--See _Coils, 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 the _duplex 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.--See _Storage Battery, Edison_.
ELECTRIC ENERGY.--The power of an electric current.
ELECTRIC OSCILLATIONS.--See _Oscillations, Electric_.
ELECTRIC SPARK.--See _Discharge, Spark_.
ELECTRICITY, NEGATIVE.--The opposite of _positive electricity_.
Negative electricity is formed of negative electrons which make up the
outside particles of an atom.
ELECTRICITY, POSITIVE.--The opposite of _negative 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.--See _Waves, Electric_.
ELECTROMOTIVE FORCE.--Abbreviated _emf_. The force that drives an
electric current along a conductor. Also loosely called
_voltage_.
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.--See _Relay, Electron_.
ELECTRON TUBE.--A vacuum tube or a gas-content tube used for any
purpose in wireless work. See _Vacuum Tube_.
ELECTROSE INSULATORS.--Insulators made of a composition material the
trade name of which is _Electrose_.
ENERGY, ELECTRIC.--See _Electric Energy_.
ENERGY UNIT.--The _joule_, 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 called _swinging_.
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 called _regenerative action_.
FERROMAGNETIC CONTROL.--See _Magnetic Amplifier_.
FILAMENT.--The wire in a vacuum tube that is heated to incandescence
and which throws off electrons.
FILAMENT RHEOSTAT.--See _Rheostat, 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.--See _Reactor, Filter_.
FIRE UNDERWRITERS.--See _Code, National Electric_.
FIXED GAP.--See _Gap_.
FLEMING VALVE.--A two-electrode vacuum tube.
FORCED OSCILLATIONS.--See _Oscillations, Forced_.
FREE OSCILLATIONS.--See _Oscillations, 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.
Carrier.--A radio frequency wave modulated by an audio frequency wave
which results in setting of _three_ radio frequency waves. The
principal radio frequency is called the carrier frequency, since it
carries or transmits the audio frequency wave.
Commercial.--(1) Alternating current that is used for commercial
purposes, namely, light, heat and power. (2) Commercial frequencies
now in general use are from 25 to 50 cycles per second.
Natural.--The pendulum and vibrating spring have a _natural frequency_
which depends on the size, material of which it is made, and the
friction which it has to overcome. Likewise an oscillation circuit has
a natural frequency which depends upon its _inductance_, _capacitance_
and _resistance_.
Radio.--(1) An oscillating current whose frequency is too high to
affect a telephone receiver and, hence, cannot be heard by the ear.
(2) Radio frequencies are usually between 20,000 and 2,000,000 cycles
per second but may be as low as 10,000 and as high as 300,000,000
cycles per second.
Spark.--The number of sparks per second produced by the discharge of a
condenser.
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.--See _Vacuum Tube._
GENERATOR TUBE.--A vacuum tube used to set up oscillations. As a
matter of fact it does not _generate_ oscillations, but changes the
initial low voltage current that flows through it into oscillations.
Also called an _oscillator tube_ and a _power tube._
GRID BATTERY.--See _Battery 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.--See _Condenser, 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.--See _Modulation, Grid._
GRID POTENTIAL.--The negative or positive voltage of the grid of a
vacuum tube.
GRID VOLTAGE.--See _Grid Potential._
GRINDERS.--The most common form of _Static,_ which see. They make a
grinding noise in the headphones.
GROUND.--See _Earth 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.--See _Wired Wireless._
HARD TUBE.--A vacuum tube in which the vacuum is _high,_ 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 the _beat_ method. (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.--See _Receptor, Heterodyne._
HIGH FREQUENCY CURRENTS.--See _Currents, High Frequency._
HIGH FREQUENCY RESISTANCE.--See _Resistance, High Frequency._
HIGH POTENTIAL CURRENTS.--See _Currents, High Potential._
HIGH VOLTAGE CURRENTS.--See _Currents, High Potential._
HONEYCOMB COILS.--See _Coils, Inductance._
HORSE-POWER.--Used in rating steam machinery. It is equal to 746
watts.
HOT WIRE AMMETER.--See _Ammeter, 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 has _reactance_ and also
_resistance,_ and when these are combined the total opposition to the
current is called _impedance._
INDUCTANCE COILS.--See _Coils, Inductance._
INDUCTANCE COIL, LOADING.--See _Coil, Loading Inductance._
INDUCTIVE COUPLING.--See _Coupling, Inductive._
INDUCTIVE REACTANCE.--See _Reactance, Inductive._
INDUCTION COIL.--See _Coil, 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.--See _Waves._
IONIC TUBES.--See _Vacuum 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 the
_Radio 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.--See _Prevention, Kick-Back._
KILOWATT.--1,000 watts.
LAMBDA.--See Pages 301, 302. [Appendix: Useful Abbreviations].
LATTICE WOUND COILS.--See _Coils, Inductance._
LIGHTNING SWITCH.--See _Switch, Lightning._
LINE RADIO COMMUNICATION.--See _Wired Wireless._
LINE RADIO TELEPHONY.--See _Telephony, Line Radio._
LITZENDRAHT.--A conductor formed of a number of fine copper wires
either twisted or braided together. It is used to reduce the _skin
effect._ See _Resistance, 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.--See _Coil, Loading._
LONG WAVES.--See _Waves._
LOOP AERIAL.--See _Aerial, Loop._
LOOSE COUPLED CIRCUITS.--See _Circuits, 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.--See _Poles, 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 the _reciprocal ohm_ or _mho._
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 a _farad._
MICROHENRY.--The millionth part of a _farad._
MICROMICROFARAD.--The millionth part of a _microfarad._
MICROHM.--The millionth part of an _ohm._
MICROPHONE TRANSFORMER.--See _Transformer, Microphone._
MICROPHONE TRANSMITTER.--See _Transmitter, 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 a _henry._
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.--See _Blub 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 the _ether,_ or _electromagnetic
waves,_ or _electric waves_ for 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.--See _Amplifiers, Multi-Stage._
MUTUAL INDUCTION.--See _Induction, 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 the _heterodyne method_ when damped waves or
modulated continuous waves are being received.
NATIONAL ELECTRIC CODE.--See _Code, National Electric._
NATIONAL ELECTRIC SAFETY CODE.--See _Code, National Electric
Safety._
NEGATIVE ELECTRICITY.--See _Electricity, Negative._
NON-SYNCHRONOUS GAP.--See _Gap, 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.--See _Circuit, Open._
OPEN CORE TRANSFORMER.--See _Transformer, Open Core._
OSCILLATION TRANSFORMER.--See _Transformer, 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.
Sustained.--Oscillations in which the damping factor is small.
Damped.--Oscillations in which the damping factor is large.
Free.--When a condenser discharges through an oscillation circuit,
where there is no outside electromotive force acting on it, the
oscillations are said to be _free._
Forced.--Oscillations that are made to surge in a circuit whose
natural period is different from that of the oscillations set up in
it.
OSCILLATION TRANSFORMER.--See _Transformer._
OSCILLATION VALVE.--See _Vacuum Tube._
OSCILLATOR TUBE.--A vacuum tube which is used to produce electric
oscillations.
OVER MODULATION.--See _Blub 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.--See _Circuits, Stand-by._
PLATE CIRCUIT REACTOR.--See _Reactor, Plate Circuit._
PLATE CURRENT.--See _Current, Plate._
PLATE MODULATION.--See _Modulation, Plate._
PLATE VOLTAGE.--See _Foliage, 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.--See _Electricity, Positive._
POTENTIAL DIFFERENCE.--The electric pressure between two charged
conductors or surfaces.
POTENTIOMETER.--A variable resistance used for subdividing the voltage
of a current. A _voltage divider._
POWER TRANSFORMER.--See _Transformer, Power._
POWER TUBE.--See _Generator Tube._
PRIMARY BATTERY.--See _Battery, 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.--See _Gap, Quenched._
RADIATION.--The emission, or throwing off, of electric waves by an
aerial wire system.
RADIO AMMETER.--See _Ammeter, Hot Wire._
RADIO FREQUENCY.--See _Frequency, Radio._
RADIO FREQUENCY AMPLIFICATION.--See _Amplification, Radio Frequency._
RADIO FREQUENCY CURRENT.--See _Current, Radio Frequency._
RADIO INSPECTOR.--See _Inspector, Radio_.
RADIOTRON.--The trade name of vacuum tube detectors, amplifiers,
oscillators and modulators made by the _Radio Corporation of America_.
RADIO WAVES.--See _Waves, 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,
in _ohms_.
RECEIVING TUNING COILS.--See _Coils, Inductance_.
RECEIVER, LOUD SPEAKING.--See _Loud 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, in _ohms_.
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 a _receptor_ to
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.--See _Amplification, 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.--See _Feed-Back Action._
REGENERATIVE AMPLIFICATION.--See _Amplification, 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. See _Resistance, High Frequency._
RESISTANCE BOX.--See _Resistor._
RESISTANCE COUPLING.--See _Coupling, 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 the _skin effect_ and 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 of _conductivity._
RESISTOR.--A fixed or variable resistance unit or a group of such
units. Variable resistors are also called _resistance boxes_ and more
often _rheostats._
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 a _natural_ period that is the
same, or nearly the same, as the period of the first oscillation
circuit.
RHEOSTAT.--A variable resistance unit. See _Resistor._
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.--See _Coil._
ROTARY GAP.--See _Gap._
ROTOR.--The rotating coil of a variometer or a variocoupler.
RUHMKORFF COIL.--See _Coil, 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.--See _Waves._
SIDE WAVES.--See _Wave 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.--See _Resistance, 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.--See _Discharge._
SPARK COIL.--See _Coil, Induction._
SPARK DISCHARGE.--See _Spark, Electric._
SPARK FREQUENCY.--See _Frequency, Spark._
SPARK GAP.--(1) A _spark gap,_ without the hyphen, means the apparatus
in which sparks take place; it is also called a _spark discharger._
(2) _Spark-gap,_ with the hyphen, means the air-gap between the
opposed faces of the electrodes in which sparks are produced.
Plain.--A spark gap with fixed electrodes.
Rotary.--A spark gap with a pair of fixed electrodes and a number of
electrodes mounted on a rotating element.
Quenched.--A spark gap formed of a number of metal plates placed
closely together and insulated from each other.
SPIDER WEB INDUCTANCE COIL.--See _Coil, Spider Web Inductance._
SPREADER.--A stick of wood, or spar, that holds the wires of the
aerial apart.
STAGGER WOUND COILS.--See _Coils, Inductance._
STAND-BY CIRCUITS.--See _Circuits, Stand-By._
STATIC.--Also called _atmospherics, 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.--See _Battery, Storage._
STRAY ELIMINATION.--A method for increasing the strength of the
signals as against the strength of the strays. See _Static._
STRAYS.--See _Static_.
STRANDED WIRE.--See _Wire, Stranded_.
SUPER-HETERODYNE RECEPTOR.--See _Heterodyne, Super_.
SWINGING.--See _Fading_.
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 called _conventional 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. See Page 307 [Appendix: Symbols Used for Apparatus].
SYNCHRONOUS GAP.--See _Gap, Synchronous_.
TELEPHONY, LINE RADIO.--See _Wired Wireless_.
THERMAL AMMETER.--See _Ammeter, 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.
A. C.--See _Power Transformer_.
Air Cooled.--A transformer in which the coils are exposed to the air.
Air Core.--With high frequency currents it is the general practice not
to use iron cores as these tend to choke off the oscillations. Hence
the core consists of the air inside of the coils.
Auto.--A single coil of wire in which one part forms the primary and
the other part the secondary by bringing out an intermediate tap.
Audio Amplifying.--This is a transformer with an iron core and is used
for frequencies up to say 3,000.
Closed Core.--A transformer in which the path of the magnetic flux is
entirely through iron. Power transformers have closed cores.
Microphone.--A small transformer for modulating the oscillations set
up by an arc or a vacuum tube oscillator.
Oil Cooled.--A transformer in which the coils are immersed in oil.
Open Core.--A transformer in which the path of the magnetic flux is
partly through iron and partly through air. Induction coils have open
cores.
Oscillation.--A coil or coils for transforming or stepping down or up
oscillating currents. Oscillation transformers usually have no iron
cores when they are also called _air core transformers._
Power.--A transformer for stepping down a commercial alternating
current for lighting and heating the filament and for stepping up the
commercial a.c., for charging the plate of a vacuum tube oscillator.
Radio Amplifying.--This is a transformer with an air core. It does not
in itself amplify but is so called because it is used in connection
with an amplifying tube.
TRANSMITTER, MICROPHONE.--A telephone transmitter of the kind that is
used in the Bell telephone system.
TRANSMITTING TUNING COILS.--See _Coils, 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 be _tuned._
Coarse Tuning.--The first adjustment in the tuning oscillation
circuits of a receptor is made with the inductance coil and this tunes
them coarse, or roughly.
Fine Tuning.--After the oscillation circuits have been roughly tuned
with the inductance coil the exact adjustment is obtained with the
variable condenser and this is _fine tuning._
Sharp.--When a sending set will transmit or a receiving set will
receive a wave of given length only it is said to be sharply tuned.
The smaller the decrement the sharper the tuning.
TUNING COILS.--See _Coils, Inductance._
TWO ELECTRODE VACUUM TUBE.--See _Vacuum 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.
Amplifier.--See _Amplifier, Vacuum Tube._
Amplifying Modulator.--A vacuum tube used for modulating and
amplifying the oscillations set up by the sending set.
Gas Content.--A tube made like a vacuum tube and used as a detector
but which contains an inert gas instead of being exhausted.
Hard.--See _Hard Tube._
Rectifier.--(1) A vacuum tube detector. (2) a two-electrode vacuum
tube used for changing commercial alternating current into direct
current for wireless telephony.
Soft.--See _Soft Tube._
Three Electrode.--A vacuum tube with three electrodes, namely a
filament, a grid and a plate.
Two Electrode.--A vacuum tube with two electrodes, namely the filament
and the plate.
VALVE.--See _Vacuum Tube._
VALVE, FLEMING.--See _Fleming Valve._
VARIABLE CONDENSER.--See _Condenser, Variable._
VARIABLE INDUCTANCE.--See _Inductance, Variable._
VARIABLE RESISTANCE.--See _Resistance, 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.--See _Condenser, 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.--See _Potentiometer._
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.--See _Receiver, Watch Case._
WATER-PIPE GROUND.--See _Ground, 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.--See _Wave Motion_.
WAVES, ELECTRIC.--Electromagnetic waves set up in and transmitted by
and through the ether.
Continuous. Abbreviated C.W.--Waves that are emitted without a break
from the aerial. Also called _undamped waves_.
Discontinuous.--Waves that are emitted periodically from the aerial.
Also called _damped waves_. Damped.--See _Discontinuous Waves_.
Intermediate.--Waves from 600 to 2,000 meters in length.
Long.--Waves over 2,000 meters in length.
Radio.--Electric waves used in wireless telegraphy and telephony.
Short.--Waves up to 600 meters in length.
Wireless.--Electric waves used in wireless telegraphy and telephony.
Undamped.--See _Continuous Waves_.
WIRELESS TELEGRAPH CODE.--See _Code, 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 called _line radio
communication; carrier frequency telephony, carrier current telephony;
guided wave telephony_ and _wired wireless._
X'S.--See _Static._
ZINCITE.--See _Detector._
WIRELESS DON'TS
AERIAL WIRE DON'TS
_Don't_ use iron wire for your aerial.
_Don't_ fail to insulate it well at both ends.
_Don't_ have it longer than 75 feet for sending out a 200-meter wave.
_Don't_ fail to use a lightning arrester, or better, a lightning
switch, for your receiving set.
_Don't_ fail to use a lightning switch with your transmitting set.
_Don't_ forget you must have an outside ground.
_Don't_ fail to have the resistance of your aerial as small as
possible. Use stranded wire.
_Don't_ fail to solder the leading-in wire to the aerial.
_Don't_ fail to properly insulate the leading-in wire where it goes
through the window or wall.
_Don't_ let your aerial or leading-in wire touch trees or other
objects.
_Don't_ let your aerial come too close to overhead wires of any kind.
_Don't_ run your aerial directly under, or over, or parallel with
electric light or other wires.
_Don't_ fail to make a good ground connection with the water pipe
inside.
TRANSMITTING DON'TS
_Don't_ attempt to send until you get your license.
_Don't_ fail to live up to every rule and regulation.
_Don't_ use an input of more than 1/2 a kilowatt if you live within 5
nautical miles of a naval station.
_Don't_ send on more than a 200-meter wave if you have a restricted or
general amateur license.
_Don't_ use spark gap electrodes that are too small or they will get
hot.
_Don't_ use too long or too short a spark gap. The right length can be
found by trying it out.
_Don't_ fail to use a safety spark gap between the grid and the
filament terminals where the plate potential is above 2,000 volts.
_Don't_ buy a motor-generator set if you have commercial alternating
current in your home.
_Don't_ overload an oscillation vacuum tube as it will greatly shorten
its life. Use two in parallel.
_Don't_ operate a transmitting set without a hot-wire ammeter in the
aerial.
_Don't_ use solid wire for connecting up the parts of transmitters.
Use stranded or braided wire.
_Don't_ fail to solder each connection.
_Don't_ use soldering fluid, use rosin.
_Don't_ think 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't_ run the wires of oscillation circuits too close together.
_Don't_ cross the wires of oscillation circuits except at right
angles.
_Don't_ set the transformer of a transmitting set nearer than 3 feet
to the condenser and tuning coil.
_Don't_ use a rotary gap in which the wheel runs out of true.
RECEIVING DON'TS
_Don't_ expect to get as good results with a crystal detector as with
a vacuum tube detector.
_Don't_ be discouraged if you fail to hit the sensitive spot of a
crystal detector the first time--or several times thereafter.
_Don't_ use a wire larger than _No. 80_ for the wire electrode of a
crystal detector.
_Don't_ try to use a loud speaker with a crystal detector receiving
set.
_Don't_ expect a loop aerial to give worthwhile results with a crystal
detector.
_Don't_ handle crystals with your fingers as this destroys their
sensitivity. Use tweezers or a cloth.
_Don't_ imbed the crystal in solder as the heat destroys its
sensitivity. Use _Wood's metal,_ or some other alloy which melts at or
near the temperature of boiling water.
_Don't_ forget that strong static and strong signals sometimes destroy
the sensitivity of crystals.
_Don't_ heat the filament of a vacuum tube to greater brilliancy than
is necessary to secure the sensitiveness required.
_Don't_ use a plate voltage that is less or more than it is rated for.
_Don't_ connect the filament to a lighting circuit.
_Don't_ use dry cells for heating the filament except in a pinch.
_Don't_ use a constant current to heat the filament, use a constant
voltage.
_Don't_ use a vacuum tube in a horizontal position unless it is made
to be so used.
_Don't_ fail to properly insulate the grid and plate leads.
_Don't_ use more than 1/3 of the rated voltage on the filament and on
the plate when trying it out for the first time.
_Don't_ fail to use alternating current for heating the filament where
this is possible.
_Don't_ fail to use a voltmeter to find the proper temperature of the
filament.
_Don't_ expect to get results with a loud speaker when using a single
vacuum tube.
_Don't_ fail to protect your vacuum tubes from mechanical shocks and
vibration.
_Don't_ fail to cut off the A battery entirely from the filament when
you are through receiving.
_Don't_ switch on the A battery current all at once through the
filament when you start to receive.
_Don't_ expect to get the best results with a gas-content detector
tube without using a potentiometer.
_Don't_ connect a potentiometer across the B battery or it will
speedily run down.
_Don't_ expect to get as good results with a single coil tuner as you
would with a loose coupler.
_Don't_ expect to get as good results with a two-coil tuner as with
one having a third, or _tickler_, coil.
_Don't_ think you have to use a regenerative circuit, that is, one
with a tickler coil, to receive with a vacuum tube detector.
_Don't_ think you are the only amateur who is troubled with static.
_Don't_ expect to eliminate interference if the amateurs around you
are sending with spark sets.
_Don't_ lay out or assemble your set on a panel first. Connect it up
on a board and find out if everything is right.
_Don't_ try to connect up your set without a wiring diagram in front
of you.
_Don't_ fail to shield radio frequency amplifiers.
_Don't_ set the axes of the cores of radio frequency transformers in a
line. Set them at right angles to each other.
_Don't_ use wire smaller than _No. 14_ for connecting up the various
parts.
_Don't_ fail to adjust the B battery after putting in a fresh vacuum
tube, as its sensitivity depends largely on the voltage.
_Don't_ fail to properly space the parts where you use variometers.
_Don't_ fail to put a copper shield between the variometer and the
variocoupler.
_Don't_ fail to keep the leads to the vacuum tube as short as
possible.
_Don't_ throw your receiving set out of the window if it _howls_. Try
placing the audio-frequency transformers farther apart and the cores
of them at right angles to each other.
_Don't_ use condensers with paper dielectrics for an amplifier
receiving set or it will be noisy.
_Don't_ expect as good results with a loop aerial, or when using the
bed springs, as an out-door aerial will give you.
_Don't_ use an amplifier having a plate potential of less than 100
volts for the last step where a loud speaker is to be used.
_Don't_ try 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't_ expect to get Arlington time signals and the big cableless
stations if your receiver is made for short wave lengths.
_Don't_ take your headphones apart. You are just as apt to spoil them
as you would a watch.
_Don't_ expect to get results with a Bell telephone receiver.
_Don't_ forget that there are other operators using the ether besides
yourself.
_Don't_ let your B battery get damp and don't let it freeze.
_Don't_ try to recharge your B battery unless it is constructed for
the purpose.
STORAGE BATTERY DON'TS
_Don't_ connect a source of alternating current direct to your storage
battery. You have to use a rectifier.
_Don't_ connect the positive lead of the charging circuit with the
negative terminal of your storage battery.
_Don't_ let the electrolyte get lower than the tops of the plates of
your storage battery.
_Don't_ fail to look after the condition of your storage battery once
in a while.
_Don't_ buy a storage battery that gives less than 6 volts for heating
the filament.
_Don't_ fail 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't_ fail to recharge your storage battery when the hydrometer
shows that the specific gravity of the electrolyte is close to 1.225.
_Don't_ keep charging the battery after the hydrometer shows that the
specific gravity is 1.285.
_Don't_ let the storage battery freeze.
_Don't_ let it stand for longer than a month without using unless you
charge it.
_Don't_ monkey 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.
EXTRA DON'TS
_Don't_ think you have an up-to-date transmitting station unless you
are using C.W.
_Don't_ use a wire from your lightning switch down to the outside
ground that is smaller than No. _4_.
_Don't_ try to operate your spark coil with 110-volt direct lighting
current without connecting in a rheostat.
_Don't_ try to operate your spark coil with 110-volt alternating
lighting current without connecting in an electrolytic interrupter.
_Don't_ try 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't_ try to tune your transmitter to send out waves of given length
by guesswork. Use a wavemeter.
_Don't_ use _hard fiber_ for panels. It is a very poor insulator where
high frequency currents are used.
_Don't_ think 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.
THE END.