100 ' ********************************* 110 ' * IBM PC BASIC VERSION A3.30 * 120 ' * FILE NAME "K" * 130 ' * TROPOSHERIC PROPAGATION * 140 ' * 1987/10 I.KATO * 150 ' ********************************* 160 KEY OFF:CLS:SCREEN 9 170 COLOR 14 180 LOCATE 1,1:PRINT "[ITEM 4] TROPOSHERIC PROPAGATION ": COLOR 7:PRINT 190 PRINT "In an actual path, propagation characteristics of microwave deeply depend upon meteorological phenomena in the atmospheric layer within ";:COLOR 3:PRINT "10 km ";:COLOR 7:PRINT "above the ground,"; 200 PRINT "that is, the troposphere. In a standard troposphere, atmosphere becomes thin andboth temperature and vapour pressure gradually decrease with increasing altitude.":PRINT 210 PRINT "Under such circumstance the refractive index also decreases, then a microwave path originally directing tangentially along the atmospheric layer will tend to curve downwards.":PRINT 220 PRINT "In order to overcome the difficulties in treating the propagation phenomena on a spherical earth, the radius of the earth can be hypothetically modified from its real value, a, so as to make the radio path straight." 240 LOCATE 18,32:PRINT "01" 260 YW=INT(50*50/12.74*5) 270 LOCATE 19,6:PRINT "RADIO PATH ON": LOCATE 20,6:PRINT "THE REAL EARTH" 280 GOSUB 1000:GOSUB 2000:GOSUB 3000 290 COLOR 6:LOCATE 23,20:PRINT "----- To proceed: Hit space key -----" 300 COLOR 7:Q$=INKEY$:IF Q$<>" " THEN 300 310 SCREEN 0:CLS 320 ' 500 LOCATE 1,1:PRINT "This modified radius of the earth is called the effective radius of earth, R and the coefficient. ";:COLOR 14:PRINT "R/a is denoted by k. ";:COLOR 7:PRINT "The value of k meteorologically" 510 PRINT "fluctuates and much depends upon regionl climates, and its average values are empirically represented by ";:COLOR 2:PRINT "6/5-4/3, 4/3 and 4/3-3/2 ";:COLOR 7:PRINT "for the high latitude" 530 PRINT "area(arctic zone), medium latitude area(temperate zone) and low latitude area (tropical zone) respectively, almost regardless of the longitude. This study" 540 PRINT "programme adopts these average values.":PRINT 550 PRINT "For a reliable microwave relay, safer provision is further recommended against occasional generation of inversed layer caused by irregular humidity and temperature distribution."; 560 PRINT " The minimum value of k is, therefore, defined for" 565 PRINT "such provision and approximated by ";:COLOR 3:PRINT "2/3";:COLOR 7:PRINT " regardless of regions." 570 COLOR 6:LOCATE 23,20:PRINT "----- menu: Hit space key -----" 580 COLOR 7:Q$=INKEY$:IF Q$<>" " THEN 580 590 CLS:SCREEN 0:RUN "ME" 1000 ' *********************** 1010 ' * graph draw sub(1) * 1020 ' *********************** 1030 WINDOW SCREEN(0,-YW)-(100,0) 1040 VIEW(194,259)-(334,291),,5 1050 FOR X=0 TO 100 1060 Y=-(100-X)*X/5 1070 IF X=0 THEN PSET(X,Y) ELSE LINE-(X,Y),2 1080 NEXT 1090 PAINT(50,-50),2 1100 LINE(0,-800)-(10,0),2 1110 PAINT( 5,-200),2 1120 FOR X=0 TO 90 1130 Y=(100-X)*X/10-800 1140 IF X=0 THEN PSET(X,Y) ELSE LINE-(X,Y),7 1150 IF X=90 THEN YE=Y 1160 NEXT 1170 LINE(90,YE)-(80,YE -70),7 1180 LINE(90,YE)-(80,YE+200),7 1190 RETURN 2000 ' *********************** 2010 ' * graph draw sub(2) * 2020 ' *********************** 2030 WINDOW SCREEN(0,-YW)-(100,0) 2040 VIEW(336,259)-(476,291),,5 2050 FOR X=0 TO 100 2060 Y=-(100-X)*X/5 2070 IF X=0 THEN PSET(X,Y) ELSE LINE-(X,Y),2 2080 NEXT 2090 PAINT(50,-50),2 2100 LINE(0,-550)-(10,0),2 2110 PAINT( 5,-200),2 2120 LINE( 0,-550)-(90,-550),7 2130 LINE(90,-550)-(80,-650),7 2140 LINE(90,-550)-(80,-450),7 2150 RETURN 3000 ' *********************** 3010 ' * graph draw sub(3) * 3020 ' *********************** 3030 WINDOW SCREEN(0,-YW)-(100,0) 3040 VIEW(480,259)-(620,291),,5 3050 FOR X=0 TO 100 3060 Y=-(100-X)*X/5 3070 IF X=0 THEN PSET(X,Y) ELSE LINE-(X,Y),2 3080 NEXT 3090 PAINT(50,-50),2 3100 LINE(0,-550)-(10,0),2 3110 PAINT( 5,-200),2 3120 FOR X=0 TO 90 3130 Y=-(55-X)*X/15-550 3140 IF X=0 THEN PSET(X,Y) ELSE LINE-(X,Y),7 3150 IF X=90 THEN YE=Y 3160 NEXT 3170 LINE(90,YE)-(80,YE-200),7 3180 LINE(90,YE)-(80,YE+ 70),7 3190 RETURN