SUBROUTINE GAIN ( ITR, DELTA, FMC, RAIN, EFF )

Argument Definitions (+ indicates altered content)
INTEGER            ITR
REAL               DELTA,     +EFF,        FMC,       +RAIN
Description
 gain.f 
         re-written 10/22/92 by Greg Hand to access all 
         antennas as external tables so they can come from any 
         source and simplify addition of new antennas. 
 
        .LT. 0 INDICATES TO CALCULATE GROUND REFLECTION LOSS 
    ITR = 1 INDICATES TRANSMITTER ANTENNA 
    ITR = 2 INDICATES RECEIVER ANTENNA 
 
    POWER GAIN OF ANTENNA AND GROUND REFLECTION LOSS 
    FOR LOSS, KOP IS ZERO OR MINUS 
DELTA IS ELEVATION ANGLE,RADIANS 
FMC  IS FREQUENCY,MHZ. 
SIGMA IS GROUND CONDUCTIVITY, MHOS/METER. 
ER IS GROUND RELATIVE DIELECTRIC CONSTANT. 
RAIN IS LOSS OR GAIN. 
 
 
    THE REFLECTION COEFFICIENTS ARE 
    KSUBV = -CV * EXP(I * PSIV),  KSUBV = CV * EXP(I * GAMMAV) 
    KSUBH = -CH * EXP(I * PSIH),  KSUBH = CH * EXP(I * GAMMAH) 
    IE  NORMALIZED WITH PSI = GAMMA + PI, PSI = GAMMA - PI 
 
    IONCAP REPORT VOLUME 1 PAGE 115 OR ITSA-1 PAGE 65 
    N O T E THIS IS NOT THE SAME AS MA AND WALTERS, ITS-74, PAGE 8
Source file:gain.f
Intrinsic Functions Called
INTEGER            IABS,       MIN0
REAL               ALOG,       FLOAT
GENERIC            ABS,        ASIN,       ATAN,       COS
GENERIC            SIN,        SQRT
Local Variables (+ indicates altered content)
INTEGER           +I,         +IAT,       +IG,        +IP1
INTEGER           +J,         +JP1
REAL              +ALPHA,     +ASXV,      +CH,        +CV
REAL              +DELTD,     +ER,        +ERT,       +OFAZ
REAL              +Q,         +R,         +RELTA,     +RHO
REAL              +RHO12,     +RX,        +RY,        +S
REAL              +SIGMA,     +T,         +U,         +V
REAL              +X,         +XAZIM,     +XDELTA,    +XFMC
REAL              +XX,        +XY,        +YX,        +YY
Referenced Common Block Variables (+ indicates altered content)
CANTENNA           INTEGER            IATS(20),  NUMANTS
CANTENNA           REAL               AEFF(30,20)
CANTENNA           REAL               ARRAY(30,91,20)
CANTENNA           REAL               BEAMMAIN(20)
CANTENNA           REAL               OFFAZIM(20)
CANTENNA           REAL               XFQE(20),  XFQS(20)
CAREAANT           INTEGER*2          IARRAY360(360,91,2)
CON                REAL               R2D
DON                REAL               BRTD,      BTRD
GEOG               REAL               EPSPAT(5)
GEOG               REAL               SIGPAT(5)