CONTENTS 
Volume I 
TECHNICAL SURVEY 
PART I SUMMARY 
CHAPTER 1, STANDARD PROPAGATION... ............. 
Introduction 1; Power Transmission 1; Optical Prop- 
erties of the Harth’s Surface and Atmosphere 2; The 
Electromagnetic Field 7. 
Cuaprer 2. Evementary THEeory or NONSTANDARD 
TREATS AUN ONE IGA isis ie a/ai'ciiysin) 2 is eles ote alten hse 
Historical 11; Refractive Index 11; Types of M Curves 
12; Ray Tracing 12; General Characteristics of Ducts 
14; Survey of Waveguide Theory 15; Reflection from 
Elevated Layers 17. 
Cnaprer 3. MrreorotocicaL MEASUREMENTS....... 
Introduction 18; Temperature and Humidity Elements 
18; The Wired Sonde 18; Refractive Index Measure- 
ments 19; Other Meteorological Instruments 20; Repre- 
sentative Observed M Curves 21. 
Cuaprer 4. TRANSMISSION EXPERIMENTS............ 
British Bxperiments 25; Experiments at the Eastern 
Coast of the U. S. 26; Experiments in Northwestern 
United States and Canada 31; Experiments in the 
SouthwesternUnited States 34; Hxperimentsat Antigua 
36; Angle-of-Arrival Measurements 38. 
CuapterR 5. GENERAL METEOROLOGY AND FORECASTING 
Introduction 39; Atmospheric Stratification 39; Condi- 
tions over Land 40; Coastal and Maritime Conditions 
41; Dynamic Effects 42; World Survey 43; Radar 
Forecasting 44. 
CHAPTER 6. SCATTERING AND ABSORPTION OF MIcRO- 
Absorption and Radar Cross Section 45; Aurcraft 
Targets 46; Ship Targets 46; Absorption and Scatter- 
ing by Clouds, Fog, Rain, Hail, and Snow 47. 
Page 
11 
18 
25 
39 
45 
PART II CONFERENCE REPORTS ON STANDARD PROPAGATION 
Cuapter 7. A GrapHicaL METHOD FOR THE DETER- 
MINATION OF STANDARD COVERAGE CHARTS....... 
Cuapter 9. THEORETICAL ANALYSIS OF HRRORS IN 
Rapar Dus To ATMOSPHERIC REFRACTION....... 
Purpose 64; Procedure 64; Application to Ground 
Radar Equipments 64; Conclusions 66. 
Carter 10. Dirrraction or Rapio WAVES OVER 
13 WETUS} Gi ee MLONA A pM ai a eae oe eR Na DSN Se da ea ii 
Introduction 71; Radar Systems 71; Types of Ground 
Radar 71; Radar Systems — Tactical Aspects 71; 
Radar Siting — Technical Aspects 72; Topography 
of Siting 72; Introduction 72; Maps and Surveys 73; 
53 
55 
64 
68 
71 
Profiles 73; Orientation 73; Visibility Problems 75; 
Diffraction of Radio Waves 77; Introduction 77; 
Wave Propagation 78; Fresnel Zones 78; Reflection 
from Rough Surfaces — Rayleigh’s Criterion 80; 
Diffraction at Obstacles 81; Fresnel Integrals 82; 
The Cornu Spiral 83; Straight Edge Diffraction 84; 
Location of Maxima and Minima 86; The Rec- 
tangular Slit 87; Diffraction by a Narrow Obstacle 
88; Multiple Slits and Obstacles 88; Limitations of 
Fresnel’s Theory 88; Permanent Echoes 89; Intro- 
duction 89; Permanent Echo Diagrams 89; Use of 
Permanent Echoes in Testing 91; Shielding 92; 
Prediction of Permanent Echoes 92; Prediction by 
Profile Method 93; Microwave Permanent Echoes 
98; The Calculation of Vertical Coverage 99; Intro- 
duction 99; The Vertical Coverage Diagram 100; 
Flat Earth Lobe Angle Calculations 101; Lobe 
Angles Corrected for Standard Earth Curvature 
102; The General Lobe Angle Formula 105; The 
Calculation of Lobes 108; Low Site Lobes 108; Lobe 
Diagrams of Medium Height Sites 110; Shoreline 
Diffraction 110; Sea Reflection with Diffuse Land 
Reflection 110; General Formula for the Reflection 
Area 111; The Modified Antenna Pattern 114; An- 
tenna Patterns 114; Local Terrain Effects 115; 
Earth Curvature Effect on Lobe Lengths 118; Coeffi- 
cient of Reflection 118; Divergence 119; Lobe 
Lengths 120; The General Lobe Formula 121; 
Calibration and Testing 124; Equipment Tests 124; 
Signal Measurements 124; Conduct of Test Flights 
125; Analysis of Test Data 126. 
Cuapter 12. VaRIATIONS IN RADAR COVERAGE....... 
Bending 127; Guided Propagation 129; Meteorological 
Factors 131; Cloud Echoes in Radar 132; Summary of 
Basic Facts Concerning Propagation at Radar Fre- 
quencies 133. 
PART III CONFERENCE REPORTS ON NONSTANDARD 
PROPAGATION 
CuartTeR 13. TROPOSPHERIC PROPAGATION AND RADIO 
METEOROLOGY 15). bls ey ee 
Fundamentals of Propagation 134; Significance of 
Propagation Problems 134; Factors Influencing 
Propagation 134; Reflection from the Ground 135; 
Refraction — Snell’s Law 1388; Refraction over a 
Curved Earth 138; Equivalent Earth Radius — 
Flat Earth Diagram 139; The Horizon — Diffraction 
141; Atmospheric Stratification and Refraction 142; 
Origin of Refractive Index Variations 142; The 
Measurement of Refractive Index 1438; Types of 
Modified Index Curves 145; Rays in a Stratified 
Atmosphere 146; The Duct — Superrefraction 147; 
Wave Picture of Guided Propagation 149; Reflection 
from an Elevated Layer 150; Operational Applica- 
tions 151; Radio Meteorology 152; Temperature and 
Moisture Gradients 152; Physical Causes of Stratifi- 
cation — Turbulence 154; Advective Ducts — 
Page 
127 
134 
