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Basic NEC with Broadcast Applications

Book Description

Basic NEC with Broadcast Applications addresses computer modeling of MF directional broadcast antennas and illustrates the assets and liabilities of the Numerical Electromagnetic Code (NEC). The book's "how to" approach reveals the fundamentals of NEC operation, teaches broadcast applications and shows the reader how to use NEC-2 to: model non-radiating networks, verify calculations, detune unused towers, design top-loaded and skirted antennas, minimize coding by moving and duplicating structures, and much more! Complete with CD, the book is an invaluable toolkit with software necessary for the design and analysis of broadcast antenna arrays.

Table of Contents

  1. Cover
  2. Basic NEC with Broadcast Applications
  3. The Purpose of Computing Is Insight, Not Numbers
  4. Full Title
  5. Copyright
  6. Dedication
  7. Contents
  8. Foreword
  9. Preface
  10. Acknowledgments
  11. About the Author
  12. CHAPTER 1 The Array Adjustment Process
    1. 1.1 The Nature of NEC-2
    2. 1.2 The Directional Antenna Adjusting Process
    3. 1.3 Local and Global Minima
    4. 1.4 The Role of NEC-2
    5. 1.5 Analysis Overview
    6. 1.6 Additional NEC-2 Benefits
    7. 1.7 Software Requirements
  13. CHAPTER 2 NEC-2 Fundamentals
    1. 2.1 Scope
    2. 2.2 The NEC-2 Engine
    3. 2.3 NEC-2 Operation
    4. 2.4 Creating the Input File
      1. 2.4.1 Naming the Files
      2. 2.4.2 Data Commands
      3. 2.4.3 Data Command Types
      4. 2.4.4 An Input File Illustration
    5. 2.5 Reading the Output File
      1. 2.5.1 The Header
      2. 2.5.2 Structure Specifications
      3. 2.5.3 Segmentation Data
      4. 2.5.4 Data Commands, Frequency, Loading, and Environment Data
      5. 2.5.5 Antenna Input Parameters
      6. 2.5.6 Currents and Locations
      7. 2.5.7 Current Moments
      8. 2.5.8 Power Budget
      9. 2.5.9 Radiation Pattern
    6. 2.6 Exercises
  14. CHAPTER 3 Modeling the Radiator
    1. 3.1 Modeling Guidelines
    2. 3.2 Guideline Summary
      1. 3.2.1 Modeling the Radiator
      2. 3.2.2 Modeling the Voltage Source
    3. 3.3 Tower Configurations
      1. 3.3.1 Single-Wire Configuration
      2. 3.3.2 Four-Wire Configuration
      3. 3.3.3 Two-Wire Configuration
      4. 3.3.4 Lattice Configuration
    4. 3.4 Viewing Tower Configuration
    5. 3.5 Exercises
  15. CHAPTER 4 Array Geometry
    1. 4.1 The Coordinate System
    2. 4.2 Array Geometry: An Example
    3. 4.3 The Array Input File
    4. 4.4 Exercises
  16. CHAPTER 5 Loads, Networks, and Transmission Lines
    1. 5.1 Modeling Impedance Loads
    2. 5.2 Modeling Nonradiating Networks
      1. 5.2.1 Typical Networks
      2. 5.2.2 Typical Network Applications
      3. 5.2.3 General Guidelines for Networks
    3. 5.3 Modeling Transmission Lines
    4. 5.4 Network Output File Listing
      1. 5.4.1 Network Descriptions
      2. 5.4.2 Source and Load Impedance to the Networks
      3. 5.4.3 Network Input Parameters
    5. 5.5 Exercises
  17. CHAPTER 6 Calculating Base Drive Voltages
    1. 6.1 Base Drive Voltages
    2. 6.2 Direct and Induced Currents
    3. 6.3 Current Moments
    4. 6.4 Development Concept
      1. 6.4.1 Unity Drive
      2. 6.4.2 Normalized Drive
      3. 6.4.3 Full Power Drive
      4. 6.4.4 Shunt Reactance and Networks
    5. 6.5 Example: A Three-Tower Array
      1. 6.5.1 Create a Unity Drive File
      2. 6.5.2 Calculate Unity Drive Current Moments
      3. 6.5.3 Solve for the Normalized Drive Voltages
      4. 6.5.4 Determine the Full Power Drive Voltages
    6. 6.6 Exercises
  18. CHAPTER 7 Using Data from the Output File
    1. 7.1 Overview
    2. 7.2 Verify the Field Ratios
    3. 7.3 Plot Far-Field Radiation Pattern
    4. 7.4 Detuning Unused Towers
      1. 7.4.1 Detuning by Base Loading
      2. 7.4.2 Detuning by Skirting
    5. 7.5 Antenna Monitor Readings
      1. 7.5.1 Optimum Height for Sample Loops
      2. 7.5.2 Arbitrary Height for Sample Loops
      3. 7.5.3 Base Current Samples
      4. 7.5.4 Base Voltage Samples
    6. 7.6 Drive Point Impedance
      1. 7.6.1 Drive Point Impedance When Using a Network
    7. 7.7 Exercises
  19. CHAPTER 8 Model by Measurement
    1. 8.1 Objective
    2. 8.2 Adjusting the Model
      1. 8.2.1 Number of Segments
      2. 8.2.2 Tower Diameter
      3. 8.2.3 Segment and Radius Taper
      4. 8.2.4 Base Capacity
      5. 8.2.5 Drive Segment Radius
    3. 8.3 Exercise
  20. CHAPTER 9 Top-Loaded and Skirted Towers
    1. 9.1 General Considerations
    2. 9.2 Top Loading
      1. 9.2.1 Estimating the Size of the Top Hat
      2. 9.2.2 Determining the Degree of Top Loading
    3. 9.3 Skirted Towers
    4. 9.4 Folded Monopole
    5. 9.5 Exercises
  21. CHAPTER 10 System Bandwidth Analysis
    1. 10.1 Introduction
    2. 10.2 System Definition
      1. 10.2.1 Tower Models
      2. 10.2.2 Tower Base Drive Voltages
    3. 10.3 Bandwidth Analysis
      1. 10.3.1 Source Impedance of the Drive Voltage
      2. 10.3.2 Intermediate Data
      3. 10.3.3 Total System Bandwidth Data
    4. 10.4 Bandwidth Conclusions
  22. CHAPTER 11 Case Studies
    1. 11.1 Comparative Data
      1. 11.2 Case Study 1: Three-Tower Array
      2. 11.2.1 Array Description: Three-Tower Array
      3. 11.2.2 Self-Impedance: Three-Tower Array
      4. 11.2.3 Antenna Monitor Reading: Three-Tower Array
      5. 11.2.4 Array Data: Three-Tower Array
      6. 11.2.5 Discussion: Three-Tower Array
      7. 11.2.6 NEC-2 Input File: Three-Tower Array
    2. 11.3 Case Study 2: Six-Tower Array, Day Pattern
      1. 11.3.1 Array Description: Six-Tower Array, Day Pattern
      2. 11.3.2 Self-impedance: Six-Tower Array, Day Pattern
      3. 11.3.3 Antenna Monitor Reading: Six-Tower Array, Day Pattern
      4. 11.3.4 Array Data: Six-Tower Array, Day Pattern
      5. 11.3.5 Discussion: Six-Tower Array, Day Pattern
      6. 11.3.6 NEC-2 Input File
    3. 11.4 Case Study 3: Six-Tower Array, Night Pattern
      1. 11.4.1 Array Description: Six-Tower Array, Night Pattern
      2. 11.4.2 Self-Impedance: Six-Tower Array, Night Pattern
      3. 11.4.3 Antenna Monitor Readings: Six-Tower Array, Night Pattern
      4. 11.4.4 Array Data: Six-Tower Array, Night Pattern
      5. 11.4.5 Discussion: Six-Tower Array, Night Pattern
      6. 11.4.6 NEC-2 Input File: Six-Tower Array, Night Pattern
    4. 11.5 Case Study 4: Tall-Tower Array
      1. 11.5.1 Array Description: Tall Towers
      2. 11.5.2 Self-Impedance: Tall Towers
      3. 11.5.3 Antenna Monitor Reading: Tall Towers
      4. 11.5.4 Array Data: Tall Towers
      5. 11.5.5 Discussion: Tall Towers
      6. 11.5.6 NEC-2 Input File: Tall Towers
  23. CHAPTER 12 Supplemental Topics
    1. 12.1 Introduction
    2. 12.2 Parallel Feeds: Network Combiners
    3. 12.3 New Structures: The NX Command
    4. 12.4 Numerical Green's Function
    5. 12.5 Ground Screens
      1. 12.5.1 The GN Command
      2. 12.5.2 The GR Command
    6. 12.6 Finite Ground
      1. 12.6.1 Reflection Coefficient Approximation
      2. 12.6.2 Sommerfeld/Norton Analysis
  24. APPENDIX A NEC-2 Input File Statements
    1. 1.0 Comment Commands (CM, CE)
    2. 2.0 Structure Geometry Commands
    3. 3.0 Program Control Commands
  25. APPENDIX B Error Messages
  26. APPENDIX C Software
    1. 1.1 Introduction
    2. 1.2 Disk Content
    3. 1.3 Essential Software
    4. 2.1 Software Installation
    5. 3.1 User Manual
      1. 3.1.1 bnec.exe
    6. 3.2 NVCOMP.EXE
    7. 3.3 NecDrv2.EXE
    8. 3.4 NECMOM.EXE
    9. 3.5 WJGRAPS.EXE
    10. 4.1 Software Support
  27. Index