100 ' ********************************

110 ' *  IBM PC BASIC VERSION A3.30  *

120 ' *  FILE NAME "SD"              *

130 ' *  SPACE DIVERSITY SYSTEM      *

140 ' *  1987/10             I.KATO  *

150 ' ********************************

160 KEY OFF:CLS:SCREEN 0

170 COLOR 14

180 LOCATE 1,1:PRINT "[ITEM 20]              SPACE DIVERSITY SYSTEM ":PRINT:        COLOR 7

190 PRINT "In-phase linear adder type is considered for the space diversity system, in     which receiving signals from two antennas vertically mounted each other at      appropriate spacing are led to the microwave combiner.":PRINT

200 PRINT "Antenna spacing differs depending upon effective reflection loss as follows.":PRINT:COLOR 3

210 PRINT "[ In case of effective reflection loss less than 10dB ]":COLOR 7

220 PRINT "Since the reflected wave interferes with the direct wave, receiving level       increases or decreases as the antenna varies in height.  The so called height   pattern is produced on a vertical plane."

230 PRINT "The space between interference maxima or minima is defined as a pitch.  Antenna spacing is fixed at ";:COLOR 3:PRINT "half of this pitch.":PRINT

240 PRINT "[ In case of effective reflection loss more than 10dB ]":COLOR 7

250 PRINT "In order to make receiving powers from two antennas be independent each other,  in other term, non-correlative, sufficient antenna spacing is required."

260 PRINT "Practically, antenna spacing should be able to support correlation coefficients ";:COLOR 3:PRINT "0.6 for 2 GHz, 0.5 for 4/5 GHz and 0.4 for 6, 7, 8 GHz."

500 COLOR 6:LOCATE 23,20:PRINT "-----To proceed:   Hit space key -----"

510 COLOR 7:Q$=INKEY$:IF Q$<>" " THEN 510

520 CLS:SCREEN 9:COLOR 7

530 GOSUB 810

540 LOCATE 1, 1:PRINT STRING$(80,"-")

550 LOCATE 2,21:PRINT "CALCULATION FORMULA"

560 LOCATE 3, 1:PRINT STRING$(80,"-"):COLOR 3

570 LOCATE 4, 1:PRINT "[ In case of effective reflection loss less than 10dB ]"

580 PRINT "HP*N: N=1,2,3,...."

590 PRINT "HP=WL/ANG*90/3.14 (half pitch)":COLOR 7

600 PRINT "WL:   wave length(m)"

610 PRINT "ANG:  included angle(rad)":COLOR 3

620 LOCATE 11,1:PRINT "[ In case of effective reflection loss more than 10dB ]"

630 PRINT "more than HP"

640 PRINT "HP=-1.1*10^3*log(LL)/(FQ*SQR(0.4*D+KK^2*S^2*(1-KK^2)*10^4))":COLOR 7

650 PRINT "D:    span distance(km)"

660 PRINT "S:    path difference between direct and reflected waves(m)"

670 PRINT "FQ:   frequency(GHz)"

680 PRINT "LL:   correlation coefficient"

690 PRINT "KK:   KK=SQR(RR^2/(RR^2+1)):RR=10^(-RFL/20):RFL=effective reflection loss(dB)"

700 COLOR 2

710 LOCATE 21,1:PRINT "This calculation will be performed in Item 23."

720 COLOR 6:LOCATE 23,10:PRINT "----- Menu: Hit space key -----"

730 COLOR 7:Q$=INKEY$:IF Q$<>" " THEN 730

740 LOCATE 23,10:PRINT SPC(69)

750 CLS:SCREEN 0:RUN "ME"

810 ' --------------------

820 ' *  graph draw sub  *

830 ' --------------------

840 VIEW(475,56)-(635,224),,5

850 WINDOW SCREEN(-10,-10)-(110,110)

860 CIRCLE(20,10),10,7,3.14159*.5,3.14159*3/2

870 CIRCLE(70,10),10,7,3.14159*3/2,3.14159*.5

880 LINE(10,10)-(10, 50),7

890 LINE(10,50)-(10,100),7,,&HF99F

900 LINE(80,10)-(80,50),7

910 LINE(80,50)-(80,100),7,,&HF99F

920 CIRCLE(70,50),10,7,3.14159*3/2,3.14159*.5

930 LINE( 20,10)-( 70,10),7,,&HF0F0

940 LINE( 20,10)-( 70,50),7,,&HF0F0

950 LINE( 90,10)-(105,10),7,,&H8888

960 LINE( 90,50)-(105,50),7,,&H8888

970 LINE(101,10)-(101,50),7,,&H8888

980 LINE( 10,90)-( 80,90),7,,&H8888

990 LINE( 0,100)-(100,100),2

1000 COLOR 14

1010 LOCATE  6,62:PRINT "T"

1020 LOCATE  6,76:PRINT "R1"

1030 LOCATE  8,77:COLOR 3:PRINT "HP":COLOR 14

1040 LOCATE 11,76:PRINT "R2"

1050 LOCATE 14,69:PRINT "D"

1060 COLOR 7:RETURN