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