=== Begin LPDA2.BAS ===
10 REM LOG PERIODIC DIPOLE ARRAY PROGRAM
20 REM "ANTENNA DESIGN USING PERSONAL COMPUTERS"
30 DATA .139,.782,.147,.822,.157,.865,.163,.892,.168,.916,.172,.928
40 DATA .174,.940,.176,.950,.178,.964
50 DIM SIG(9),TAU(9)
60 REM FILL ARRAYS
70 FOR I=1 TO 9
80 READ SIG(I),TAU(I)
90 NEXT I
100 PI=3.141593
110 KEY OFF
120 CLS
130 COLOR 1,0
140 PRINT "LOG-PERIODIC ARRAY DESIGN"
150 COLOR 4,0
160 PRINT
170 INPUT "WHAT IS THE LOWER FREQUENCY(MHz)";FMIN
180 INPUT "WHAT IS THE UPPER FREQUENCY(MHz)";FMAX
190 INPUT "WHAT IS THE DESIRED GAIN(dB)(BETWEEN 8 AND 12)";D0
200 IF D012 THEN GOTO 190
210 INPUT "WHAT IS THE RADIUS OF THE LARGEST DIPOLE(meters)";A1
220 COLOR 14,0
230 REM INTERPOLATE TO FIND SIGMA, TAU
240 I1%=2*D0-15
250 IF I1%<1 THEN I1%=1
260 IF I1%>9 THEN I1%=9
270 I2%=I1%+1
280 IF I2%>9 THEN I2%=9
290 DI=(I1%+15)/2
300 S=SIG(I1%)+2*(D0-DI)*(SIG(I2%)-SIG(I1%))
310 T=TAU(I1%)+2*(D0-DI)*(TAU(I2%)-TAU(I1%))
320 PRINT
330 PRINT "SIGMA,TAU=",S,T
340 ALP=ATN((1-T)/(4*S))
350 XL=300/FMIN
360 LOD=.25*XL/A1
370 F=LOD/(1+LOD)
380 DO=0
390 AO=A1
400 LO=.48*F*XL
410 XL=300/FMAX
420 LMIN=.48*XL
430 I=0
440 PRINT "DIPOLE #  SPACING  LENGTH   RADIUS"
450 I=I+1
460 PRINT USING " ##      ##.####  ##.####   .####";I,DO,LO,AO
470 IF LO * Origin: KB6PI's Antenna Farm * San Diego, CA (1:202/909.10)