VLF Radio Engineering

International Series of Monographs in Electromagnetic Waves

1st Edition - January 1, 1967
Author: Arthur D. Watt
Editors: A. L. Cullen, V. A. Fock, J. R. Wait
Language: English
eBook ISBN:
9 7 8 - 1 - 4 8 3 1 - 5 2 3 0 - 1

Electromagnetic Waves, Volume 14: VLF Radio Engineering provides a detailed coverage of the fields involved in very low frequency (VLF) radio engineering. This book serves as a… Read more

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Electromagnetic Waves, Volume 14: VLF Radio Engineering provides a detailed coverage of the fields involved in very low frequency (VLF) radio engineering. This book serves as a guide for applying the information in the solution of practical problems. Comprised of seven chapters, this volume starts with an overview of the communications aspect following the flow of information carrying energy from the transmitting to receiving locations. This text then presents the complete systems that consider the interrelationship of the various factors. Other chapters explain the basic concept of a VLF antenna, which is a vertical electric monopole over a perfectly conducting flat plane. This book discusses as well the radio wave propagation at VLF, which has been studied theoretically and experimentally for many years. The final chapter deals with the primary components of a complete VLF radio system. This book is a valuable resource for radio engineers, scientists, and researchers.

Preface

Chapter 1. Introduction

1.1 Background and Instructions

1.2 Units

1.3 Coordinate Systems

1.3.1 Vectors

1.3.2 Fields

1.3.3 Vector Multiplication

1.3.4 Phasors

Chapter 2. Transmitting Antenna

2.0 List of Symbols

2.1 Basic Concepts

Radiation Efficiency

Calculation of Antenna Bandwidth

Effects of Base or Feed Shunt Capacity

Power Bandwidth Product

2.2 Vertical Supports

2.2.1 Wind and Wind Loading

2.2.2 Tower and Mast Steel Requirements and Approximate Costs

2.3 Top Loading

2.3.1 Capacity of Wire Segments

2.3.2 Physical Characteristics of Guys and Elevated Wires

2.3.3 Wires and Cables

2.3.4 Insulators

2.4 Ground Systems

H Field Loss Resistive Component

E Field Loss Resistive Component

Vertical Electric Fields

Power Loss and Resistive Component for E Field Losses

Wire Surface Interface Losses

Calculation of H Field Ground Resistance Components When the Surface Impedance is Constant or Has a Simple Radial Variation

2.5 Conductor and Tuning Coil Properties

Skin Effect

Proximity Effect

Losses in Solenoid Coils

2.6 Corona

Corona Formation and Spark Breakdown

Frequency Effects

Electric Fields of Typical Geometrical Forms

Corona Onset Voltage and Power Loss Calculations

Effective Capacity Change

Power Loss

2.7 Mode Excitation Factor

Antenna Directivity

2.8 Characteristics of Actual VLF Antennas

2.8.1 Historical Review

2.8.2 Electrical Parameters

2.8.3 Summary of Early VLF Antennas

2.8.4 Characteristics of Major Existing Antennas

2.9 Optimum Size and Multiple Unit Considerations

Chapter 3. Propagation

Foreword

3.0 List of Symbols

3.1 Basic Concepts

3.2 Ground Wave Propagation

3.2.1 Surface Impedance Concepts

3.2.2 Mixed Paths

3.3 Ray Theory and Skywave Field Calculations

3.3.1 Ray Path Geometry

3.3.2 Effective Antenna Patterns and Ray Launching Factors

3.3.3 Ionospheric Reflection Coefficients

3.3.4 Ionospheric Convergence Factor

3.3.5 Multiple Hop Considerations

3.3.6 Height Gain Factors

3.3.7 Calculation of Total Field Employing both Ground and Sky Waves

3.4 Waveguide Modes

3.4.1 Introductory Flat-Earth Theory

3.4.2 Theory of Higher Order Flat-Earth Modes

3.4.3 Spherical-Earth Theory (by J. R. Wait)

3.4.4 Approximate Approaches to Spherical-Earth Modes

3.5 Mode Field Calculations and Comparison with Observed Fields

3.5.1 Mode Field Equations

3.5.2 Excitation Factors and Height Gain

3.5.3 Attenuation Rates

3.5.4 Phase Velocity

3.5.5 Short-Term Amplitude and Phase Variations

3.5.6 Field Strength and Phase Versus Distance

3.5.7 Group Velocity

3.6 Magneto-Ionic Modes (Whistlers)

3.7 Effects of High Altitude Nuclear Explosions

Chapter 4. Receiving Antenna

4.0 List of Symbols

4.1 Basic Concepts

4.2 Inverse Launching or Coupling Efficiency

4.3 Characteristics of E Field Antennas

4.3.1 Vertical Whips

4.3.2 Grounded Horizontal Wire Antennas

4.4 Characteristics of H Field Antennas

4.4.1 Loops

4.5 Thermal Noise Levels and Equivalent Noise Fields

4.5.1 Directly Coupled Antennas

4.5.2 Transformer Coupled Antennas

4.5.3 Effective Noise Field with a Specified Receiver

4.6 The Loop Antenna in a Conducting Medium

4.7 Aircraft Antennas

4.7.1 Types Employed

4.7.2 Calibration Techniques

4.8 Aircraft Precipitation Static

4.8.1 Charge Generation Mechanism

4.8.2 Corona Discharge and Noise Fields

4.8.3 Aircraft Dischargers and Noise Suppression

Chapter 5. Atmospheric Radio Noise Fields

5.0 List of Symbols

5.1 Basic Concepts

5.2 Noise Sources

5.2.1 Lightning Characteristics

5.2.2 Thunderstorm Distribution

5.2.3 Extraterrestrial Sources

5.3 Median Level

5.3.1 Level Variation vs. Frequency

5.3.2 Level Variation vs. Geographic Location and Time

5.4 Short-Term Statistics

5.4.1 Amplitude Probability Distributions

5.4.2 Pulse Spacing Statistics

Chapter 6. Modulation, Frequency Spectra, and Receiving System Performance

6.0 List of Symbols

6.1 Basic Concepts

6.2 Communication Theory and Modulation Considerations

6.2.1 Information Transmission Theory

6.2.2 Modulation Methods and Theory

6.3 Frequency Spectra and Bandwidth Requirements

6.3.1 Periodic Functions and the Fourier Series

6.3.2 Nonperiodic Functions and the Fourier Integral

6.3.3 Impulse and Step Function Response of Linear Low Pass Filters

6.3.4 Spectra of On-Off Keyed Transmitters

6.3.5 Frequency Spectra of FSK Transmitters

6.4 Carrier to Noise and Error Calculations

6.4.1 Statistics of a Carrier plus Thermal and VLF Atmospheric Noise

6.4.2 Carrier to Noise Requirements for Precise Frequency Measurement

6.4.3 Comparison of Calculated and Measured Errors

6.5 Typical Communication Systems

6.5.1 Data Rates, Keying Rates, and Bandwidths

6.5.2 System Performance Factors

Chapter 7. Complete Systems Considerations

7.0 List of Symbols

7.1 Basic Concepts

7.2 Calculation of Power Requirements and Performance Reliability

7.2.1 Power Requirements for a Specified Path

7.2.2 Performance Reliability for a Specified Power

7.2.3 Prediction Reliability

7.3 Calculation of Bandwidth Requirements

Transmitting Antenna Bandwidth

Degradation of System Performance Due to Limited Transmitter System Bandwidth

7.4 Economic Factors in Design

7.4.1 Transmitting System Cost Factors

7.4.2 Selection of Optimum Efficiency

Appendices

A. Abbreviations

B. Conversion Coefficients

C. Electric and Magnetic Fields Produced by a Time Varying Vertical Current

D. Antenna Current Voltage Relationship and Power Radiating Capabilities near Self-Resonance

Voltage and Current Distribution (Constant Impedance)

Voltage and Current Distribution (Varying Impedance)

E. Electrical Properties of the Ionosphere

E.1 Effective Permitivity of an Ionized Medium (without a Magnetic Field or Collisions)

E.2 Effects of Collisions (no Magnetic Field)

E.3 Effect of a Magnetic Field

E.4 Electron Density and Collisional Frequencies

F. Solar Radiation and Sunspot Cycles

Long-Term Periodic Fluctuations of Solar Activity

Nonperiodic and Short-Term Variations in Solar Radiation

Cosmic Ray Intensity Variations

G. Sun's Zenith Angle and Sunrise-Sunset Times

H. Geomagnetic Field

Answers to Problems

Author Index

Subject Index

Other Titles in the Series