10 REM DISHCALC PROGRAM
20 REM CALCULATES DISH ANTENNA PARAMETERS
30 REM FROM MEASURED DIMENSIONS
40 REM VERSION 1.2 OF 16 MAY 1999
50 REM BY ED MUNN, W6OYJ
60 REM GAIN FORMULA ASSUMES DISH APERTURE EFFICIENCY = 55 %
70 KEY OFF:CLS
80 PRINT"DISHCALC PROGRAM GIVES ANTENNA PARAMETERS FROM DIMENSIONS"
90 PRINT
100 PRINT"CHOOSE UNITS YOU PREFER:"
110 PRINT"INCHES = 1"
120 PRINT"FEET = 2"
130 PRINT"CENTIMETERS = 3"
140 PRINT"METERS = 4"
150 PRINT
160 INPUT"WHICH ";C
170 IF C=1 THEN C$="INCHES"
180 IF C=2 THEN C$="FEET"
190 IF C=3 THEN C$="CENTIMETERS"
200 IF C=4 THEN C$="METERS"
210 PRINT"ENTER DISH DIAMETER IN ";C$;
220 INPUT D
230 PRINT"ENTER DEPTH OF DISH IN ";C$;
240 INPUT X
250 PRINT
260 R=D/2
270 LF=(R*R)/(4*X)
280 PRINT"FOCAL LENGTH IS APPROX. = ";LF;" ";C$
290 R=LF/D
300 PRINT"F.L./DIA. RATIO IS = ";R
310 FA=ATN((D/2)/(LF-X))
320 FA=FA*57.2958*2
330 PRINT"FEED ANGLE IS = ";FA;" DEGREES"
340 REM CONVERT D TO FEET
350 IF C=1 THEN D=D/12
360 IF C=3 THEN D=.03281*D
370 IF C=4 THEN D=3.281*D
380 PRINT
390 INPUT"ENTER FREQUENCY IN MHZ = ";F
400 PRINT"**************************"
410 L1=LOG(F)/LOG(10)
420 L2=LOG(D)/LOG(10)
430 G=(20*L1)+(20*L2)-52.6
450 PRINT"ANTENNA GAIN IS = ";G;" DB"
460 REM DISH ANTENNA 3DB BEAMWIDTH (FULL)
470 B=(70000!) /(F*D)
480 PRINT"3 DB FULL BEAMWIDTH IS ";B;" DEGREES"
490 PRINT
500 INPUT"DO ANOTHER FREQUENCY (Y/N) ";Q$
510 IF Q$="y" GOTO 380
520 IF Q$="Y" GOTO 380
540 END