CHAPTER I Fundamental Ideas and Laws Electrons — Electric fields — Induced charges — Electric current — Conductors and insulators — Continuous and alternating current — Wave shape — Magnetic fields — Units — Induced e.m.f. — Self-induction — Coupling — Capacity — Oscillograph — Current flow in inductive and condensive circuits — Time constant — Alternating-current flow in various circuits — Effect of frequency — Transients in inductive circuits — Resonance — Decrement — Decrement from resonance curve — Parallel circuits — Various types of coupling — Effect of neighboring circuits on resistance and reactance — Resonance in coupled circuits — Resonance in electrically long circuits 1-110 CHAPTER II Resistance — Inductance — Capacity General concept of resistance — Various factors affecting resistance — Skin effect and its elimination — Skin effect in coils — Eddy currents in iron cores — Characteristics of iron core coils — Resistance of arc and spark — Resistance of an antenna. Coefficient of self-induction — Self-induction of single vertical wire — Single horizontal wire — Single circular turn — Single layer solenoid — Flat spiral — Toroid — Single layer square coil — Flat square coil — Multilayer coil — Mutual induction of two single turns — Coaxial solenoids — Two- wire antenna — Two concentric coils — Two coaxial spirals. Capacity in general — Capacity of an isolated sphere — Parallel circular plates — Single vertical wire — Mutual capacity of two horizontal wires — Multiplate condenser — Forms of condensers — Specific inductive capacity — Losses on condensers — Phase difference of a condenser — Internal capacity coils — Natural period of coils. 111-178 CHAPTER III General View of Radio Communication Wave motion in water — Electro-magnetic waves — Velocity of propagation — Different types of waves — Spark telegraphy — Continuous-wave telegraphy — Radio telephony — Receiving station — Selectivity — Interference — Simultaneous sending and receiving — Atmospheric disturbance — Elimination of atmospheric disturbance — Attentuation of waves — Day and night variation in signal strength — Seasonal variation — Amounts of power required — "Freak" transmission 179-201 CHAPTER IV Laws of Oscillating Circuits Condenser discharge through inductance — Effect of condenser leakage — Frequency — Wave-length — Voltage and current relations — Damping and decrement — Decay of current, voltage and energy — Effect of spark gap — Number of waves in a train — Effective value of damped sine wave current — Effect of neighboring circuits upon oscillatory discharge — Coupled pendulums — Oscillations in coupled circuits — Phases and amplitudes of currents — Vector diagram of currents in coupled circuits — Frequency of beats — Quenching gap — Oscillatory circuit excited by continuous voltage — Oscillatory circuit excited by application of alternating voltage — Periodic disturbances in oscillatory circuit — Oscillatory circuit excited by pulse — Impulse excitation of parallel resonant circuit — Oscillatory circuit excited by damped sine wave and resonance curve for such a case 202-274 CHAPTER V Spark Telegraphy Normal transmission equipment — Battery and coil — Alternators for radio transmitters — Transformers — Condensers — Resonance conditions in audio frequency circuit — Different types of spark gaps — Oscillation transformer — Energy distribution curves of a transmitter and effect of coupling — Adjustment of a spark transmitter — Elements of a receiving set — Need of a rectifier — Types of coupling — The telephone receiver — Crystal rectifiers — Vacuum tube detector — Adjustment of receiving set — Wave-lengths and ranges of transmission in spark telegraphy — Arrangement of apparatus in typical transmitting stations 275-363 CHAPTER VI Vacuum Tubes and Their Operation in Typical Circuits Possibility of electron emission — Theoretical prediction of electron evaporation — Electron atmosphere — Power required to produce emission — Two-electrode vacuum tube — Fleming valve — Space charge and its effects — Three-electrode tube — Deforest audion — Potential distribution in three-electrode tube — Uses of three-electrode tube — Operating limits of a tube — Effect of gas — Ionization — Evacuation of a tube — Detection of gas in a tube — Characteristic curves of typical three-electrode tubes — Free grid potential — Equation of plate current — Resistance of tube circuits — Capacity of input circuit — Three-electrode tube as detector — Action of grid condenser — Triode as generator of alternating current power — Output and efficiency — Heating of plates — Phase relations in a triode — Possibility of self-excitation — Triode as detector of continuous wave signals — Analysis of typical circuits used for self-excitation with conditions necessary for oscillation — Starting and stopping oscillations — Parasitic frequencies — Circuits used with triode as detector — Criterion for oscillation in detector tube — Peculiar noises in autodyne circuits — Regenerative circuits for spark signal reception — Triodes in parallel — Alternating-current power supply for plate circuit — Special forms of tubes — Detailed study of triode as power converter — Triode characteristics when used as amplifier 364-577 CHAPTER VII Continuous-wave Telegraphy Advantages of continuous-wave telegraphy — High-frequency generators — Poulsen arc — Elementary theory of oscillating arc — Types of oscillation of arc — Commercial form of arc — High-frequency alternators — Alexanderson alternator — Goldschmidt alternator — Frequency transformers using iron cores — Marconi multiple-gap generator — Methods of signaling used with different generators — Reception of continuous-wave signals — Tone wheel — Heterodyne — Effect of upper harmonics on beat reception — Arrangement of apparatus in continuous-wave tube transmitters 578-645 CHAPTER VIII Radio Telephony Field of use — The transmitter — The receiver — Modulation — The microphone transmitter — Analysis of modulation — Percentage modulation — Schemes for modulation — The vacuum tube in radio telephony — Heising scheme of modulation and its analysis — Alexanderson scheme of modulation — Analysis of modulated wave — Oscillating tube as receiver — Effect of decrements upon quality of speech — Multiplex radio telephony — Amounts of power used and distances covered — Arrangement of apparatus in a commercial set — Simultaneous transmission and reception 646-693 CHAPTER IX Antennae and Radiation Radiation from simple antenna — Effects of moving electric and magnetic fields — Open and closed electric systems — Fields involved in radiation — Radiated field at a distance from the antenna — Radiation from a coil — Excitation of the transmitting antenna — Various types of antennae and their characteristics — Relation between simple antenna and coil antenna — Antennae for air ships — Underwater antennae — Ground antennae — Law of radiation from an antenna — Radiation resistance — Current in receiving antenna — Merits of different types of antennae — Limitation of transmission formulae — Counterpoises — Antenna resistance — Natural wave-length of an antenna — Current and voltage distribution along an antenna and effect of loading — Direction finders — Reliability of direction finders — Transient effects in an antenna 694-780 CHAPTER X Wavemeters and Their Use Frequency and wave-length — Principle of wavemeter — Extending range of a wavemeter — Schemes for indicating resonance — Classification of resonance indicators — Condenser for even scale — Autodyne wavemeter — Measuring the wave-length of a transmitter — Energy distribution — Decrement determination with spark transmitter — Determination of decrement of wavemeter — Decremeter — Measurement of constants of an antenna — Mutual induction and coefficient of coupling determination — An improvised wave-meter 781-823 CHAPTER XI Amplifiers Amplifiers in general — Characteristics of triodes — Effect of plate circuit resistance and reactance — Classification of amplifiers — Transformer-repeating amplifiers — Construction of transformers for audio-frequency — Impedance of telephone receivers — Connections of transformer-repeating amplifier — Transformer-repeating amplifiers for high frequencies — Resistance amplifier — Proper resistances for repeating — Grid condenser and leak — Inductance-repeating amplifier — Filters and their characteristics — Stability of amplifiers — Tube noises — Arrangement of apparatus in amplifiers 824-879 CHAPTER XII Radio Experiments Resonance curves — Buzzer-generator and crystal detector characteristics — Study and use of wavemeter — Setting up and adjusting a spark transmitter — Measurement of antenna constants — Continuous current characteristics of three-electrode tube — Three-electrode tube as detector of damped waves — Determination of tube constants — Triode as power converter — Triode as source of power in self-exciting circuit — Resistance measurements at high frequency — Oscillating triode as receiver of continuous-wave signals — Study of the audio-frequency amplifier — Study of radio-telephone set 880-919 Digitized by Google.

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