100 CLS : KK = 111.12: DR = 57.296: NN = 60: SS = 69.06
200 HTH$ = "Adelaide": HAT$ = "34.99S": HON$ = "138.54E"
ZZ$ = HAT$: GOSUB 600: HAT = ZZ: HAT = HAT / DR
ZZ$ = HON$: GOSUB 600: HON = ZZ
GC$ = "GREAT CIRCLE DISTANCE & BEARING": PRINT GC$
PRINT "FROM     Home QTH ", HTH$: PRINT "         Latitude ", HAT$; " degrees"
PRINT "         Longitude ", HON$; " degrees"
PRINT : PRINT "Enter QTH values in degrees and decimals"
PRINT "with S or N after latitude & E or W after longitude e.g. 168.2E"
PRINT : INPUT "TO       Remote QTH name  "; QTH$
INPUT "         Latitude         "; LAT$
ZZ$ = LAT$: GOSUB 600: LAT = ZZ: LAT = LAT / DR
INPUT "         Longitude        "; LON$
ZZ$ = LON$: GOSUB 600: LON = ZZ
LDF = (HON - LON) / DR
EE = SIN(HAT) * SIN(LAT) + COS(HAT) * COS(LAT) * COS(LDF)
DD = -ATN(EE / SQR(ABS(1 - EE * EE))) + 1.57079
CC = (SIN(LAT) - SIN(HAT) * EE) / (COS(HAT) * SIN(DD))
IF CC >= 1 THEN CC = 0: GOTO 300 ELSE IF CC <= -1 THEN CC = 180 / DR: GOTO 300
CC = -ATN(CC / SQR(ABS(1 - CC * CC))) + 1.57079
300 C = INT(CC * DR)
IF SIN(LDF) < 0 THEN C = 360 - C
R = 180 + C
IF R >= 360 THEN R = R - 360
PRINT : PRINT : PRINT GC$
PRINT "TO "; QTH$; "         FROM "; HTH$
PRINT : PRINT "DISTANCE =", INT(KK * DD * DR); " km"
PRINT , INT(SS * DD * DR); " miles"
PRINT , INT(NN * DD * DR); " nautical miles"
PRINT : PRINT "BEARING  =", C; " degrees", "[Short Path]"
PRINT , R; " degrees", "[Long Path]"
400   PRINT : INPUT "Any more to do [Y or N] "; K$
IF K$ = "Y" OR K$ = "y" THEN 100
500 CLS : END
600 YY = 1
IF RIGHT$(ZZ$, 1) = "E" OR RIGHT$(ZZ$, 1) = "e" THEN YY = -1
IF RIGHT$(ZZ$, 1) = "S" OR RIGHT$(ZZ$, 1) = "s" THEN YY = -1
ZZ = YY * VAL(LEFT$(ZZ$, LEN(ZZ$) - 1))
700 RETURN