2 # A perl Minimuf calculator, nicked from the minimuf program written in
5 # Translated and modified for my own purposes by Dirk Koopman G1TLH
7 # as fixed by Steve Franke K9AN
9 # Copyright (c) 1999 Dirk Koopman G1TLH
11 # The original copyright:-
12 #/***********************************************************************
14 # * Copyright (c) David L. Mills 1994-1998 *
16 # * Permission to use, copy, modify, and distribute this software and *
17 # * its documentation for any purpose and without fee is hereby *
18 # * granted, provided that the above copyright notice appears in all *
19 # * copies and that both the copyright notice and this permission *
20 # * notice appear in supporting documentation, and that the name *
21 # * University of Delaware not be used in advertising or publicity *
22 # * pertaining to distribution of the software without specific, *
23 # * written prior permission. The University of Delaware makes no *
24 # * representations about the suitability this software for any *
25 # * purpose. It is provided "as is" without express or implied *
28 # ***********************************************************************
30 # MINIMUF 3.5 from QST December 1982
31 # (originally in BASIC)
42 @EXPORT = qw($pi $d2r $r2d $halfpi $pi2 $VOFL $R $hE $hF $GAMMA $LN10
43 $MINBETA $BOLTZ $NTEMP $DELTAF $MPATH $GLOSS $SLOSS
49 use POSIX qw(:math_h);
51 use vars qw($pi $d2r $r2d $halfpi $pi2 $VOFL $R $hE $hF $GAMMA $LN10
52 $MINBETA $BOLTZ $NTEMP $DELTAF $MPATH $GLOSS $SLOSS
60 $VOFL = 2.9979250e8; # velocity of light
61 $R = 6371.2; # radius of the Earth (km)
62 $hE = 110; # mean height of E layer (km)
63 $hF = 320; # mean height of F layer (km)
64 $GAMMA = 1.42; # geomagnetic constant
65 $LN10 = 2.302585; # natural logarithm of 10
66 $MINBETA = (10 * $d2r); # min elevation angle (rad)
67 $BOLTZ = 1.380622e-23; # Boltzmann's constant
68 $NTEMP = 290; # receiver noise temperature (K)
69 $DELTAF = 2500; # communication bandwidth (Hz)
70 $MPATH = 3; # multipath threshold (dB)
71 $GLOSS = 3; # ground-reflection loss (dB)
72 $SLOSS = 10; # excess system loss
73 $noise = 10 * log10($BOLTZ * $NTEMP * $DELTAF) + 30;
80 return ($x > 0) ? 1 : -1;
84 # MINIMUF 3.5 (From QST December 1982, originally in BASIC)
89 my $flux = shift; # 10-cm solar flux
90 my $month = shift; # month of year (1 - 12)
91 my $day = shift; # day of month (1 - 31)
92 my $hour = shift; # hour of day (utc) (0 - 23)
93 my $lat1 = shift; # transmitter latitude (deg n)
94 my $lon1 = shift; # transmitter longitude (deg w)
95 my $lat2 = shift; # receiver latitude (deg n)
96 my $lon2 = shift; # receiver longitude (deg w)
98 my $ssn; # sunspot number dervived from flux
99 my $muf; # maximum usable frequency
100 my $dist; # path angle (rad)
101 my ($a, $p, $q); # unfathomable local variables
105 my ($k1, $k6, $k8, $k9);
107 my ($ftemp, $gtemp); # volatile temps
109 # Determine geometry and invariant coefficients
111 $ftemp = sin($lat1) * sin($lat2) + cos($lat1) * cos($lat2) *
113 $ftemp = -1 if ($ftemp < -1);
114 $ftemp = 1 if ($ftemp > 1);
115 $dist = acos($ftemp);
117 $k6 = 1 if ($k6 < 1);
120 $a = (sin($lat1) - $p * cos($dist)) / ($q * sin($dist));
121 $y1 = 0.0172 * (10 + ($month - 1) * 30.4 + $day);
122 $y2 = 0.409 * cos($y1);
123 $ftemp = 2.5 * $dist / $k6;
124 $ftemp = $halfpi if ($ftemp > $halfpi);
125 $ftemp = sin($ftemp);
126 $m9 = 1 + 2.5 * $ftemp * sqrt($ftemp);
130 for ($k1 = 1 / (2 * $k6); $k1 <= 1 - 1 / (2 * $k6); $k1 += abs(0.9999 - 1 / $k6)) {
131 $gtemp = $dist * $k1;
132 $ftemp = $p * cos($gtemp) + $q * sin($gtemp) * $a;
133 $ftemp = -1 if ($ftemp < -1);
134 $ftemp = 1 if ($ftemp > 1);
135 $y3 = $halfpi - acos($ftemp);
136 $ftemp = (cos($gtemp) - $ftemp * $p) / ($q * sqrt(1 - $ftemp * $ftemp));
137 $ftemp = -1 if ($ftemp < -1);
138 $ftemp = 1 if ($ftemp > 1);
139 $ftemp = $lon2 + SGN(sin($lon1 - $lon2)) * acos($ftemp);
140 $ftemp += $pi2 if ($ftemp < 0);
141 $ftemp -= $pi2 if ($ftemp >= $pi2);
142 $ftemp = 3.82 * $ftemp + 12 + 0.13 * (sin($y1) + 1.2 * sin(2 * $y1));
143 $k8 = $ftemp - 12 * (1 + SGN($ftemp - 24)) * SGN(abs($ftemp - 24));
144 if (cos($y3 + $y2) <= -0.26) {
148 $ftemp = (-0.26 + sin($y2) * sin($y3)) / (cos($y2) * cos($y3) + 0.001);
149 $k9 = 12 - atan($ftemp / sqrt(abs(1 - $ftemp * $ftemp))) * 7.639437;
150 $t = $k8 - $k9 / 2 + 12 * (1 - SGN($k8 - $k9 / 2)) * SGN(abs($k8 - $k9 / 2));
151 $t4 = $k8 + $k9 / 2 - 12 * (1 + SGN($k8 + $k9 / 2 - 24)) * SGN(abs($k8 + $k9 / 2 - 24));
152 $c0 = abs(cos($y3 + $y2));
153 $t9 = 9.7 * pow($c0, 9.6);
154 $t9 = 0.1 if ($t9 < 0.1);
156 $g8 = $pi * $t9 / $k9;
157 if (($t4 < $t && ($hour - $t4) * ($t - $hour) > 0.) || ($t4 >= $t && ($hour - $t) * ($t4 - $hour) <= 0)) {
158 $ftemp = $hour + 12 * (1 + SGN($t4 - $hour)) * SGN(abs($t4 - $hour));
159 $ftemp = ($t4 - $ftemp) / 2;
160 $g0 = $c0 * ($g8 * (exp(-$k9 / $t9) + 1)) * exp($ftemp) / (1 + $g8 * $g8);
162 $ftemp = $hour + 12 * (1 + SGN($t - $hour)) * SGN(abs($t - $hour));
163 $gtemp = $pi * ($ftemp - $t) / $k9;
164 $ftemp = ($t - $ftemp) / $t9;
165 $g0 = $c0 * (sin($gtemp) + $g8 * (exp($ftemp) - cos($gtemp))) / (1 + $g8 * $g8);
166 $ftemp = $c0 * ($g8 * (exp(-$k9 / $t9) + 1)) * exp(($k9 - 24) / 2) / (1 + $g8 * $g8);
167 $g0 = $ftemp if ($g0 < $ftemp);
170 $ftemp = (1 + $ssn / 250) * $m9 * sqrt(6 + 58 * sqrt($g0));
171 $ftemp *= 1 - 0.1 * exp(($k9 - 24) / 3);
172 $ftemp *= 1 + 0.1 * (1 - SGN($lat1) * SGN($lat2));
173 $ftemp *= 1 - 0.1 * (1 + SGN(abs(sin($y3)) - cos($y3)));
174 $muf = $ftemp if ($ftemp < $muf);
180 # spots(flux) - Routine to map solar flux to sunspot number.
182 # THis routine was done by eyeball and graph on p. 22-6 of the 1991
183 # ARRL Handbook. The nice curve fitting was done using Mathematica.
187 my $flux = shift; # 10-cm solar flux
188 my $ftemp; # double temp
190 return 0 if ($flux < 65);
192 $ftemp = $flux - 200.6;
193 $ftemp = 108.36 - .005896 * $ftemp * $ftemp;
194 } elsif ($flux < 213) {
195 $ftemp = 60 + 1.0680 * ($flux - 110);
197 $ftemp = $flux - 652.9;
198 $ftemp = 384.0 - 0.0011059 * $ftemp * $ftemp;
203 # ion - determine paratmeters for hop h
205 # This routine determines the reflection zones for each hop along the
206 # path and computes the minimum F-layer MUF, maximum E-layer MUF,
207 # ionospheric absorption factor and day/night flags for the entire
212 my $h = shift; # hop index
213 my $d = shift; # path angle (rad)
214 my $fcF = shift; # F-layer critical frequency
215 my $ssn = shift; # current sunspot number
223 # various refs to arrays
224 my $daynight = shift; # ref to daynight array one per hop
229 my $beta; # elevation angle (rad)
230 my $psi; # sun zenith angle (rad)
231 my $dhop; # hop angle / 2 (rad)
232 my $dist; # path angle (rad)
233 my $phiF; # F-layer angle of incidence (rad)
234 my $phiE; # E-layer angle of incidence (rad)
235 my $fcE; # E-layer critical frequency (MHz)
236 my $ftemp; # double temp
239 # Determine the path geometry, E-layer angle of incidence and
240 # minimum F-layer MUF. The F-layer MUF is determined from the
241 # F-layer critical frequency previously calculated by MINIMUF
242 # 3.5 and the secant law and so depends only on the F-layer
243 # angle of incidence. This is somewhat of a crock; however,
244 # doing it with MINIMUF 3.5 on a hop-by-hop basis results in
245 # rather serious errors.
248 $dhop = $d / ($h * 2);
249 $beta = atan((cos($dhop) - $R / ($R + $hF)) / sin($dhop));
250 $ftemp = $R * cos($beta) / ($R + $hE);
251 $phiE = atan($ftemp / sqrt(1 - $ftemp * $ftemp));
252 $ftemp = $R * cos($beta) / ($R + $hF);
253 $phiF = atan($ftemp / sqrt(1 - $ftemp * $ftemp));
254 $absorp->[$h] = $mufE->[$h] = $daynight->[$h] = 0;
255 $mufF->[$h] = $fcF / cos($phiF);;
256 for ($dist = $dhop; $dist < $d; $dist += $dhop * 2) {
258 # Calculate the E-layer critical frequency and MUF.
261 $psi = zenith($dist, $lat1, $lon1, $b1, $b2, $lats, $lons);
263 $fcE = .9 * pow((180. + 1.44 * $ssn) * $ftemp, .25) if ($ftemp > 0);
264 $fcE = .005 * $ssn if ($fcE < .005 * $ssn);
265 $ftemp = $fcE / cos($phiE);
266 $mufE->[$h] = $ftemp if ($ftemp > $mufE->[$h]);
268 # Calculate ionospheric absorption coefficient and
269 # day/night indicators. Note that some hops along a
270 # path can be in daytime and others in nighttime.
273 if ($ftemp > 100.8 * $d2r) {
274 $ftemp = 100.8 * $d2r;
275 $daynight->[$h] |= 2;
277 $daynight->[$h] |= 1;
279 $ftemp = cos(90. / 100.8 * $ftemp);
280 $ftemp = 0. if ($ftemp < 0.);
281 $ftemp = (1. + .0037 * $ssn) * pow($ftemp, 1.3);
282 $ftemp = .1 if ($ftemp < .1);
283 $absorp->[$h] += $ftemp;
289 # pathloss(freq, hop) - Compute receive power for given path.
291 # This routine determines which of the three ray paths determined
292 # previously are usable. It returns the hop index of the best of these
293 # or zero if none are found.
297 my $hop = shift; # minimum hops
298 my $freq = shift; # frequency
299 my $txpower = shift || 20; # transmit power
300 my $rsens = shift || -123; # receiver sensitivity
301 my $antgain = shift || 0; # antenna gain
303 my $daynight = shift; # ref to daynight array one per hop
312 my $level; # max signal (dBm)
313 my $signal; # receive signal (dBm)
314 my $ftemp; # double temp
318 # Calculate signal and noise for all hops. The noise level is
319 # -140 dBm for a receiver bandwidth of 2500 Hz and noise
320 # temperature 290 K. The receiver sensitivity is assumed -123
321 # dBm (0.15 V at 50 Ohm for 10 dB S/N). Paths where the signal
322 # is less than the noise or when the frequency exceeds the F-
323 # layer MUF are considered unusable.
327 for ($h = $hop; $h < $hop + 3; $h++) {
328 $daynight->[$h] &= ~(4 | 8 | 16);
329 if ($freq < 0.85 * $mufF->[$h]) {
331 # Transmit power (dBm)
333 $signal = $txpower + $antgain + 30;
337 $signal -= 32.44 + 20 * log10($path->[$h] * $freq) + $SLOSS;
341 $ftemp = $R * cos($beta->[$h]) / ($R + $hE);
342 $ftemp = atan($ftemp / sqrt(1 - $ftemp * $ftemp));
343 $signal -= 677.2 * $absorp->[$h] / cos($ftemp) / (pow(($freq + $GAMMA), 1.98) + 10.2);
345 # Ground reflection loss
347 $signal -= $h * $GLOSS;
348 $dB2->[$h] = $signal;
350 # Paths where the signal is greater than the
351 # noise, but less than the receiver sensitivity
352 # are marked 's'. Paths below the E-layer MUF
353 # are marked 'e'. When comparing for maximum
354 # signal, The signal for these paths is reduced
355 # by 3 dB so they will be used only as a last
359 $daynight->[$h] |= 4 if ($signal < $rsens);
360 if ($freq < $mufE->[$h]) {
361 $daynight->[$h] |= 8;
364 if ($signal > $level) {
371 # We have found the best path. If this path is less than 3 dB
372 # above the RMS sum of the other paths, the path is marked 'm'.
374 return 0 if ($j == 0);
377 for ($h = $hop; $h < $hop + 3; $h++) {
378 $ftemp += exp(2 / 10 * $dB2->[$h] * $LN10) if ($h != $j);
380 $ftemp = 10 / 2 * log10($ftemp);
381 $daynight->[$j] |= 16 if ($level < $ftemp + $MPATH);
386 # zenith(dist) - Determine sun zenith angle at reflection zone.
390 my $dist = shift; # path angle
391 my $txlat = shift; # tx latitude (rad)
392 my $txlong = shift; # tx longitude (rad)
393 my $txbearing = shift; # tx bearing
394 my $pathangle = shift; # 'b1'
395 my $lats = shift; # subsolar latitude
396 my $lons = shift; # subsolar longitude
398 my ($latr, $lonr); # reflection zone coordinates (rad)
399 my $thetar; # reflection zone angle (rad)
400 my $psi; # sun zenith angle (rad)
402 # Calculate reflection zone coordinates.
404 $latr = acos(cos($dist) * sin($txlat) + sin($dist) * cos($txlat) * cos($txbearing));
405 $latr += $pi if ($latr < 0);
406 $latr = $halfpi - $latr;
407 $lonr = acos((cos($dist) - sin($latr) * sin($txlat)) / (cos($latr) * cos($txlat)));
408 $lonr += $pi if ($lonr < 0);
409 $lonr = - $lonr if ($pathangle < 0);
410 $lonr = $txlong - $lonr;
411 $lonr -= $pi2 if ($lonr >= $pi);
412 $lonr += $pi2 if ($lonr <= -$pi);
413 $thetar = $lons - $lonr;
414 $thetar = $pi2 - $thetar if ($thetar > $pi);
415 $thetar -= $pi2 if ($thetar < - $pi);
417 # Calculate sun zenith angle.
419 $psi = acos(sin($latr) * sin($lats) + cos($latr) * cos($lats) * cos($thetar));
420 $psi += $pi if ($psi < 0);
424 # official minimuf version of display
430 my $daynight = shift;
435 return " " unless $h;
437 if (($daynight->[$h] & 3) == 3) {
439 } elsif ($daynight->[$h] & 1) {
441 } elsif ($daynight->[$h] & 2) {
444 if ($daynight->[$h] & 4) {
446 } elsif ($daynight->[$h] & 16) {
451 return sprintf("%4.0f%s%1d%s", $dB2->[$h] - $rsens, $c1, $h, $c2)
460 my $daynight = shift;
464 return " " unless $h;
466 if ($daynight->[$h] & 4) {
468 } elsif ($daynight->[$h] & 16) {
473 my $l = $dB2->[$h] - $rsens;
477 my $plus = (($l / 6) >= $s + 0.5) ? '+' : ' ';
479 return "$c2". "S$s$plus";