GLOSSARY 
1) Velocity of wav» propagation = c/n 
2) Argument of Fresnel’s integral 
8) Dimensionless parameter = d/d7 
Voltage 
Noise voltage 
Power per unit area 
Incident power per unit area 
Scattered power per unit area at the receiver 
Amplitude of ratio of diffracted field to free-space 
field 
Impedance 
Antenna impedance 
Load impedance 
1) Attenuation constant, real part of propagation 
constant 7 
2) Angle made by ray with the horizontal 
Angle of elevation of diffracting edge as seen from 
transmitter, receiver 
1) Bearing of the sun 
2) Phase constant, imaginary part of propagation 
constant 
Angle between ray from transmitter, receiver, and 
horizontal at diffracting edge 
1) Propagation constant = a + 78 
2) Angle between horizontal at base of transmitter 
and line joining transmitter base to receiver 
~ Angle between the direct ray and the horizontal at 
the transmitter 
1) Declination of the sun 
2) Angle of phase retardation due to path-length 
difference between direct and reflected rays 
3) Ground parameter depending on complex dielec- 
tric constant 
Path-length difference between direct and reflected 
rays =r — 74 
= (2hih2)/d 
Correction factor for Ap 
Bandwidth 
Variable used in diffraction region 
€0. 
Wa. 
513 
Dielectric constant of free space 
1 
= 8.854 x 10-27 =—— 10-* 
5 367 
Complex dielectric constant = ¢ — je; 
Imaginary part of dielectric constant = 600A 
Real part of dielectric constant 
1) Phase-angle lag due to diffraction 
2) Dimensionless distance variable for curved-earth 
diffraction 
1) Angle between horizontal at transmitter base 
and horizontal at point of reflection 
2) Angle of tilt of scattering cylinder 
Wavelength 
Permeability of free space = 4710-7 
Permeability relative to free space 
Angle between reflected ray and horizontal at trans- 
* mitter 
1) Radius of curvature 
2) Amplitude of reflection coefficient 
1) Conductivity 
2) Radar cross section 
1) Complex mode numbers 
2) Half beam-width angle 
1) Phase angle of reflection coefficient 
2) Latitude 
= —7 =phase angle of reflection coefficient 
relative to a perfect reflector 
Distance function for the first mode 
1) Phase-angle difference between currents in 
dipole-antenna array 
2) Angle between direct or reflected ray and the 
horizontal at the reflection point 
3) Height variable in the diffraction region 
Angle between direct ray and horizontal at reflec- 
tion point 
Angular velocity = 27f 
Total phase lag between direct and reflected rays 
=$'+6=o¢-7+6 
