Jeb 
HA. 
GLOSSARY 
1) Radius of the earth 
2) Radius of scattering plate, sphere, or cylinder 
Gain factor = ApAp 
Gain factor for doublet antennas in free space, 
adjusted for maximum transfer of power = 
8\/87d 
Plane-earth factor 
Path-gain factor 
Gain-factor curve parameter 
di — ad, 
dat a; 
Bandwidth 
1) Velocity of light in free space 
nthe 
Real part of Fresnel’s integral 
Distance from center of transmitting antenna to a 
point in space measured along earth surface 
Free-space distance for field of strength H 
: f d 
Normalized free-space distance = aa 
Distance from transmitter, receiver to reflecting 
point measured along the earth’s surface 
Distance from transmitter, receiver to the radio 
horizon measured along the earth’s surface 
Line of sight distance measured along the earth’s 
surface = d7 +dp 
Maximum radar range 
1) Divergence factor for spherical earth 
2) Aperture of reflector 
1) Water-vapor pressure 
2) Coefficient for height-gain function 
Electric-field strength 
Maximum free-space field strength of a doublet 
transmitter at distance d 
Radiation field strength at one meter from trans- 
mitter 
1) Frequency 
2) Focal length of paraboloid reflector 
Cutoff frequency of a wave guide 
Height-gain function 
Height-gain function for the n** mode 
Fraction of maximum radiation field strength in the 
direction of direct, reflected rays 
Noise figure 
Shadow factor for all modes 
1) Receiver gain 
2) Exponential factor of height-gain function for! 
elevated antennas ; 
Correction to g(2) 
Transmitting antenna gain 
Receiving antenna gain 
Radar gain of a target 
Height above grouna 
Height of transmitter, receiver above ground 
Height of transmitter, receiver above tangent plane 
at point of reflection 
Critical height distinguishing high and low antennas 
located in diffraction region = 30A2/8 
Virtual height of obstructing screen 
1) Magnetic field strength 
2) Height of a reflecting or diffracting obstruction 
Height-gain function for low antennas 
Hour angle of the sun 
Fe 
GH 
vd. 
RMS current 
Input current to antenna or circuit 
vaa 
1) Boltzmann’s constant 
2) Factor multiplying earth’s radius to account for 
atmospheric refraction 
1) Amplitude of generalized reflection coefficient 
2) Echo constant of a target 
1) Length of a doublet 
2) Height coefficient to include effect of earth’s 
constants and wavelength 
1) Effective length of a doublet 
2) Characteristic length or scattering coefficient of 
a target 
3) Radar length of a target 
1) Ratio of radius of curvature of a ray to the radius 
of the earth = p,’a: 
da? 
2) ™ = hah + hs) 
Modified index of refraction 
1) Index of refraction 
2) Number of elements in an antenna array 
Lobe numbers 
Lobe variable for imperfect reflection 
Noise figure 
1) Total pressure of the atmosphere 
2) Dimensionless parameter = d,/dr 
Distance coefficient to include earth constants 
Power 
Power output of a transmitting doublet 
Power delivered by a receiving doublet to a matched 
load 
Minimum power detectable by a receiver 
Noise power 
Power received by load circuit of receiying antenna, 
Scattered power 
Dimensionless parameter = d2/d 
Parameter determining phase of beam reflected by 
&r 
the earth = Ean 
1) Distance from center of antenna to a point in 
space (usually replaced by d in applications) 
2) Height wavelength factor 
3) Pattern or chart parameter 
4) Path length of reflected ray 
Path length of direct ray 
1) Resistance 
2) Plane-earth reflection coefficient = pew 
3) Path-difference parameter = (kaA)/(hidT) 
Resistive component of antenna impedance 
Relative humidity in per cent 
Resistive component of load impedance 
Radiation resistance of an antenna 
1) Spacing between dipoles in an antenna array 
2) Coefficient of distance for shadow factor 
3) Dimensionless coordinate = d;/d 
1) Scattering cross section 
2) Area 
Imaginary part of Fresnel’s integral 
1) Time 
2) Pulse width 
3) Degrees centigrade 
Absolute temperature 
Dimensionless coordinate = he/hi 
