100 ' **************************************** 110 ' * IBM PC BASIC VERSION A3.30 * 120 ' * FILE NAME "CL" * 130 ' * PATH CLEARANCE AT RIDGE POINT * 140 ' * 1987/10 I.KATO * 150 ' **************************************** 160 KEY OFF:CLS:SCREEN 9 170 COLOR 14 180 DIM Y(100) 190 LOCATE 1,1:PRINT "[ITEM 9] PATH CLEARANCE AT RIDGE POINT ":COLOR 7 200 PRINT "A necessary path clearance at a ridge point is obtained from the value of First Fresnel zone radius in Item 5, and used for calculation of ridge diffraction loss(Item 10)." 230 PRINT "----- calculation formula -----" 240 PRINT "CL=H1-D1/D*(H1-H2)-D1*D2/(2*k*6370)*1000-HS" 260 PRINT "H1=A POINT HEIGHT(m):H2=B POINT HEIGHT(m)" 270 PRINT "HS=RIDGE ALTITUDE(m):D=A-B DISTANCE(km)" 280 PRINT "D1=A-RIDGE DISTANCE(km):D2=D-D1" 290 PRINT "k=COEFFCIENT OF EQUIVALENT EARTH RADIUS" 300 PRINT STRING$(42,"-") 310 MH(1)=700:MH(2)=500:MH(3)=600:VMD=100:VLD=40 320 FOR I=1 TO 3:VH(I)=100-MH(I)/700*100:NEXT 330 GOSUB 1000:GOSUB 2000 340 COLOR 4:LOCATE 12,1:PRINT "[direct wave clearance]":COLOR 7 350 PRINT "A direct wave clearance, denoted by DCL, means a gap" 360 PRINT "between the centre of direct wave and the top of ridge." 370 PRINT "A plus sign signifies a clearance margin," 380 PRINT "while minus sign interception." 390 COLOR 14:PRINT "[reflected wave clearance]":COLOR 7 400 PRINT "F and RCL represent a reflection point and a" 410 PRINT "path clearance at a ridge point." 420 PRINT "In this calculation, the path is imaginatively" 430 PRINT "regarded as AFB' (i,e. B' is equivalent for an" 440 PRINT "image of point B)." 450 COLOR 6:LOCATE 23,10:PRINT "----- menu: Hit space key -----" 460 COLOR 7:Q$=INKEY$:IF Q$<>" " THEN 460 470 CLS:SCREEN 0:RUN "ME" 1000 ' ------------------------------- 1010 ' * data input graph draw sub * 1020 ' ------------------------------- 1030 C=12.74*4/3 1040 WINDOW SCREEN(0,-100)-(100,50) 1050 VIEW(492,70)-(632,315),,5 1060 ' ground surface 1070 FOR X=0 TO 100 1080 Y=-(100-X)*X/C/10 1090 IF X=0 THEN PSET(X,Y) ELSE LINE-(X,Y),2 1100 Y(X)=Y 1110 NEXT 1120 LINE(0, 0)-( 5, -80),2 :'A 1130 LINE(5,-80)-( 10,Y(10)),2 :'A 1140 LINE(90,Y(90))-(95,-30),2 :'B 1150 LINE(95, -30)-(100, 0),2 :'B 1160 LINE(40,Y(40))-(45,-45),2 :'R 1170 LINE(45,-45)-(50,Y(50)),2 :'R 1180 PAINT( 5,-70),2,2 1190 PAINT(95,-20),2,2 1200 PAINT(45,-40),2,2 1210 LINE( 5,-80)-(95, -30),4 :'A-B 1220 LINE( 5,-80)-(60,Y(60)),14 :'A-F-B 1230 LINE( 60,Y(60))-(95,-30),14 :'A-F-B 1240 LINE( 90,Y(90))-(95, 30),2 :'image B 1250 LINE( 95, 30)-(100, 0),2 :'image B 1260 LINE( 5,-80)-(95,30),14,,&H8888 :'A-F-image B 1270 ' 1280 LINE(45,-45)-(45,-58),7,,&H8888 1290 LINE(45,-45)-(80,-45),7,,&H8888 1300 LINE(45,-58)-(80,-58),7,,&H8888 1310 LINE(45,-30)-(80,-30),7,,&H8888 1320 LOCATE 7,63:PRINT "A" 1330 LOCATE 11,75:PRINT "DCL" 1340 LOCATE 13,73:PRINT "RCL":LOCATE 13,79:PRINT "B" 1350 LOCATE 16,72:PRINT "F" 1360 LOCATE 21,79:PRINT "B'" 1370 RETURN 2000 ' ------------------------------- 2010 ' * data input graph draw sub * 2020 ' ------------------------------- 2030 WINDOW SCREEN(0,0)-(100,100) 2040 VIEW(370,210)-(490,315),,5 2050 LINE(10,30)-(50,30),3 2060 LINE(10,70)-(50,70),3 2070 CIRCLE(10,50),18,3,1.57,4.71,1.5 2080 CIRCLE(50,50),18,3,,,1.5 2090 PAINT(20,50),3,3 2100 LINE(45,50)-(90,50),4 2110 LINE(50,30)-(50,50),7,,&H8888 2120 LINE(65,100)-(70, 70),2 2130 LINE(70, 70)-(75,100),2 2140 PAINT(70,90),2 2150 LINE(85, 50)-(85,70),7,,&H8888 2160 LINE(70, 70)-(85,70),7,,&H8888 2170 LOCATE 16,48:PRINT "First Fresnel" 2180 LOCATE 17,48:PRINT "zone radius" 2190 LOCATE 20,61:PRINT "clearance" 2200 RETURN