LIST OF FIGURES

Fig. 1.--Simple Receiving Set

Fig. 2.--Simple Transmitting Set

(A) Fig. 3.--Flat Top, or Horizontal Aerial

(B) Fig. 3.--Inclined Aerial

(A) Fig. 4.--Inverted L Aerial

(B) Fig. 4.--T Aerial

Fig. 5.--Material for a Simple Aerial Wire System

(A) Fig. 6.--Single Wire Aerial for Receiving

(B) Fig. 6.--Receiving Aerial with Spark Gap Lightning Arrester

(C) Fig. 6.--Aerial with Lightning Switch

Fig. 7.--Two-wire Aerial

(A) Fig. 8.--Part of a Good Aerial

(B) Fig. 8.--The Spreaders

(A) Fig. 9.--The Middle Spreader

(B) Fig. 9.--One End of Aerial Complete

(C) Fig. 9.--The Leading in Spreader

(A) Fig. 10.--Cross Section of Crystal Detector

(B) Fig. 10.--The Crystal Detector Complete

(A) Fig. 11.--Schematic Diagram of a Double Slide Tuning Coil

(B) Fig. 11.--Double Slide Tuning Coil Complete

(A) Fig. 12.--Schematic Diagram of a Loose Coupler

(B) Fig. 12.--Loose Coupler Complete

(A) Fig. 13.--How a Fixed Receiving Condenser is Built up

(B) Fig. 13.--The Fixed Condenser Complete

(C) and (D) Fig. 13.--Variable Rotary Condenser

Fig. 14.--Pair of Wireless Headphones

(A) Fig. 15.--Top View of Apparatus Layout for Receiving Set No. 1

(B) Fig. 15.--Wiring Diagram for Receiving Set No. 1

(A) Fig. 16.--Top View of Apparatus Layout for Receiving Set No. 2

(B) Fig. 16.--Wiring Diagram for Receiving Set No. 2

Fig. 17.--Adjusting the Receiving Set

(A) and (B) Fig. 18.--Types of Spark Coils for Set No. 1

(C) Fig. 18.--Wiring Diagram of Spark Coil

Fig. 19.--Other Parts for Transmitting Set No. 1

(A) Fig. 20.--Top View of Apparatus Layout for Sending Set No. 1

(B) Fig. 20.--Wiring of Diagram for Sending Set No. 1

Fig. 21.--Parts for Transmitting Set No. 2

(A) Fig. 22.--Top View of Apparatus Layout for Sending Set No. 2

(B) Fig. 22.--Wiring Diagram for Sending Set No. 2

Fig. 23.--Using a 110-volt Direct Current with an Alternating current Transformer

Fig. 24.--Principle of the Hot Wire Ammeter

Fig. 25.--Kinds of Aerial Switches

Fig. 26.--Wiring Diagram for a Complete Sending and Receiving Set No. 1

Fig. 27.--Wiring Diagram for Complete Sending and Receiving Set No. 2

Fig. 28.--Water Analogue for Electric Pressure

Fig. 29.--Water Analogues for Direct and Alternating Currents

Fig. 30.--How the Ammeter and Voltmeter are Used

Fig. 31.--Water Valve Analogue of Electric Resistance

(A) and (B) Fig. 32.--How an Electric Current is Changed into Magnetic Lines of Force and These into an Electric Current

(C) and (D) Fig. 32.--How an Electric Current Sets up a Magnetic Field

Fig. 33.--The Effect of Resistance on the Discharge of an Electric Current

Fig. 34.--Damped and Sustained Mechanical Vibrations

Fig. 35.--Damped and Sustained Electric Oscillations

Fig. 36.--Sound Wave and Electric Wave Tuned Senders and Receptors

Fig. 37.--Two Electrode Vacuum Tube Detectors

Fig. 38.--Three Electrode Vacuum Tube Detector and Battery Connections

Fig. 39.--A and B Batteries for Vacuum Tube Detectors

Fig. 40.--Rheostat for the A or Storage-battery Current

(A) Fig. 41.--Top View of Apparatus Layout for Vacuum Tube Detector Receiving Set

(B) Fig. 41.--Wiring Diagram of a Simple Vacuum Tube Receiving Set

Fig. 42.--Grid Leaks and How to Connect them Up

Fig. 43.--Crystal Detector Receiving Set with Vacuum Tube Amplifier (Resistance Coupled)

(A) Fig. 44.--Vacuum Tube Detector Receiving Set with One Step Amplifier (Resistance Coupled)

(B) Fig. 44.--Wiring Diagram for Using One A or Storage Battery with an Amplifier and a Detector Tube

(A) Fig. 45.--Wiring Diagram for Radio Frequency Transformer Amplifying Receiving Set

(B) Fig. 45.--Radio Frequency Transformer

(A) Fig. 46.--Audio Frequency Transformer

(B) Fig. 46.--Wiring Diagram for Audio Frequency Transformer Amplifying Receiving Set. (With Vacuum Tube Detector and Two Step Amplifier Tubes)

(A) Fig. 47.--Six Step Amplifier with Loop Aerial

(B) Fig. 47.--Efficient Regenerative Receiving Set (With Three Coil Loose Coupler Tuner)

Fig. 48.--Simple Regenerative Receiving Set (With Loose Coupler Tuner)

(A) Fig. 49.--Diagram of Three Coil Loose Coupler

(B) Fig. 49.--Three Coil Loose Coupler Tuner

Fig. 50.--Honeycomb Inductance Coil

Fig. 51.--The Use of the Potentiometer

Fig. 52.--Regenerative Audio Frequency Amplifier Receiving Set

Fig. 53.--How the Vario Coupler is Made and Works

Fig. 54.--How the Variometer is Made and Works

Fig. 55.--Short Wave Regenerative Receiving Set (One Variometer and Three Variable Condensers)

Fig. 56.--Short Wave Regenerative Receiving Set (Two Variometer and Two Variable Condensers)

Fig. 57.--Wiring Diagram Showing Fixed Loading Coils for Intermediate Wave Set

Fig. 58.--Wiring Digram of Intermediate Wave Receptor with One Vario Coupler and 12 Section Bank-wound Inductance Coil

Fig. 59.--Wiring Diagram Showing Long Wave Receptor with Vario Couplers and 8 Bank-wound Inductance Coils

Fig. 60.--Wiring Diagram of Long Wave Autodyne, or Self-heterodyne Receptor (Compare with Fig. 77)

Fig. 61.--Wiring Diagram of Long Wave Separate Heterodyne Receiving Set

Fig. 62.--Cross Section of Bell Telephone Receiver

Fig. 63.--Cross Section of Wireless Headphone

Fig. 64.--The Wireless Headphone

Fig. 65.--Arkay Loud Speaker

Fig. 66.--Amplitone Loud Speaker

Fig. 67.--Amplitron Loud Speaker

Fig. 68.--Magnavox Loud Speaker

Fig. 69.--Schematic Diagram of an Atom

Fig. 70.--Action of Two-electrode Vacuum Tube

(A) and (B) Fig. 71.--How a Two-electrode Tube Acts as Relay or a Detector

(C) Fig. 71.--Only the Positive Part of Oscillations Goes through the Tube

(A) and (B) Fig. 72.--How the Positive and Negative Voltages of the Oscillations Act on the Electrons

(C) Fig. 72.--How the Three-electrode Tube Acts as Detector and Amplifier

(D) Fig. 72.--How the Oscillations Control the Flow of the Battery Current through the Tube

Fig. 73.--How the Heterodyne Receptor Works

Fig. 74.--Separate Heterodyne Oscillator

(A) Fig. 75.--Apparatus for Experimental C. W. Telegraph Transmitter.

(B) Fig. 75.--Apparatus for Experimental C. W. Telegraph Transmitter.

Fig. 76.--Experimental C. W. Telegraph Transmitter

Fig. 77.--Apparatus of 100-mile C. W. Telegraph Transmitter

Fig. 78.--5- to 50-watt C. W. Telegraph Transmitter (with a Single Oscillation Tube)

Fig. 79.--200-mile C. W. Telegraph Transmitter (with Two Tubes in Parallel)

Fig. 80.--50-watt Oscillator Vacuum Tube

Fig. 81.--Alternating Current Power Transformer (for C. W. Telegraphy and Wireless Telephony)

Fig. 82.--Wiring Diagram for 200- to 500-mile C. W. Telegraph Transmitting Set. (With Alternating Current.)

Fig. 83.--Wiring Diagram for 500- to 1000-mile C. W. Telegraph Transmitter

Fig. 84.--Standard Microphone Transmitter

Fig. 85.--Wiring Diagram of Short Distance Wireless Telephone Set. (Microphone in Aerial Wire.)

Fig. 86.--Telephone Induction Coil (used with Microphone Transmitter).

Fig. 87.--Microphone Transformer Used with Microphone Transmitter

Fig. 88.--Magnetic Modulator Used with Microphone Transmitter

(A) Fig. 89.--Wiring Diagram of 25--to 50-mile Wireless Telephone. (Microphone Modulator Shunted Around Grid-leak Condenser)

(B) Fig. 89.--Microphone Modulator Connected in Aerial Wire

Fig. 90.--Wiring Diagram of 50- to 100-mile Wireless Telephone Transmitting Set

Fig. 91.--Plate and Grid Circuit Reactor

Fig. 92.--Filter Reactor for Smoothing Out Rectified Currents

Fig. 93.--100- to 200-mile Wireless Telephone Transmitter

(A) and (B) Fig. 94.--Operation of Vacuum Tube Oscillators

(C) Fig. 94.--How a Direct Current Sets up Oscillations

Fig. 95.--Positive Voltage Only Sets up Oscillations

Fig. 96.--Rasco Baby Crystal Detector

Fig. 97.--How the Tuning Coil is Made

Fig. 98.--Mesco loop-ohm Head Set

Fig. 99.--Schematic Layout of the $5.00 Receiving Set

Fig. 100.--Wiring Diagram for the $5.00 Receiving Set