
Instead of using a frequency counter, you can try this to 
coarsely determine frequency of your particular crystal.

In this case it is +73 ppm, you can set this frequency with
1000,073 kHz and do fine calibration with calfreq afterwards.
The crystal should not change its frequency too much, 
it should be suifficient to do this coarse calibration only once.
Fine calibration is necessary every time you want to use Loran-C.


: coarse ( -- )
  cr \ Try to coarsely determine crystal frequency in -100 ppm to +100 ppm range.
  offsetmeasurement

  101 -100 do
    i . ." ppm "  0 i  0,001 f* 1000,0 d+ ( 2dup f. ) khz
    32 samplegris
    puffermaximum ."  Maximum: " . cr
  loop
  cr
;


An example how output looks like:
There are three maximums, but the one at +73 ppm is clearly the strongest one.

coarse
-100 ppm Crystal too slow, Tack: 167  Maximum: 875
-99 ppm Crystal too slow, Tack: 169  Maximum: 869
-98 ppm Crystal too slow, Tack: 171  Maximum: 879
-97 ppm Crystal too slow, Tack: 172  Maximum: 1068
-96 ppm Crystal too slow, Tack: 174  Maximum: 951
-95 ppm Crystal too slow, Tack: 176  Maximum: 1005
-94 ppm Crystal too slow, Tack: 178  Maximum: 866
-93 ppm Crystal too slow, Tack: 180  Maximum: 2306
-92 ppm Crystal too slow, Tack: 182  Maximum: 831
-91 ppm Crystal too slow, Tack: 184  Maximum: 814
-90 ppm Crystal too slow, Tack: 186  Maximum: 1029
-89 ppm Crystal too slow, Tack: 188  Maximum: 911
-88 ppm Crystal too slow, Tack: 190  Maximum: 937
-87 ppm Crystal too slow, Tack: 192  Maximum: 878
-86 ppm Crystal too slow, Tack: 194  Maximum: 1095
-85 ppm Crystal too slow, Tack: 197  Maximum: 873
-84 ppm Crystal too slow, Tack: 199  Maximum: 1112
-83 ppm Crystal too slow, Tack: 201  Maximum: 838
-82 ppm Crystal too slow, Tack: 204  Maximum: 1163
-81 ppm Crystal too slow, Tack: 206  Maximum: 776
-80 ppm Crystal too slow, Tack: 209  Maximum: 1189
-79 ppm Crystal too slow, Tack: 211  Maximum: 1179
-78 ppm Crystal too slow, Tack: 214  Maximum: 1084
-77 ppm Crystal too slow, Tack: 217  Maximum: 1295
-76 ppm Crystal too slow, Tack: 220  Maximum: 998
-75 ppm Crystal too slow, Tack: 223  Maximum: 796
-74 ppm Crystal too slow, Tack: 226  Maximum: 852
-73 ppm Crystal too slow, Tack: 229  Maximum: 829
-72 ppm Crystal too slow, Tack: 232  Maximum: 895
-71 ppm Crystal too slow, Tack: 235  Maximum: 1008
-70 ppm Crystal too slow, Tack: 239  Maximum: 1274
-69 ppm Crystal too slow, Tack: 242  Maximum: 1001
-68 ppm Crystal too slow, Tack: 246  Maximum: 1199
-67 ppm Crystal too slow, Tack: 249  Maximum: 1204
-66 ppm Crystal too slow, Tack: 253  Maximum: 1377
-65 ppm Crystal too slow, Tack: 257  Maximum: 1446
-64 ppm Crystal too slow, Tack: 261  Maximum: 1408
-63 ppm Crystal too slow, Tack: 265  Maximum: 1694
-62 ppm Crystal too slow, Tack: 269  Maximum: 1674
-61 ppm Crystal too slow, Tack: 274  Maximum: 1700
-60 ppm Crystal too slow, Tack: 278  Maximum: 2179
-59 ppm Crystal too slow, Tack: 283  Maximum: 2189
-58 ppm Crystal too slow, Tack: 288  Maximum: 2068
-57 ppm Crystal too slow, Tack: 293  Maximum: 1978
-56 ppm Crystal too slow, Tack: 298  Maximum: 2289
-55 ppm Crystal too slow, Tack: 304  Maximum: 2381
-54 ppm Crystal too slow, Tack: 309  Maximum: 1886
-53 ppm Crystal too slow, Tack: 315  Maximum: 1945
-52 ppm Crystal too slow, Tack: 321  Maximum: 2046
-51 ppm Crystal too slow, Tack: 327  Maximum: 1662
-50 ppm Crystal too slow, Tack: 334  Maximum: 1299
-49 ppm Crystal too slow, Tack: 341  Maximum: 2628
-48 ppm Crystal too slow, Tack: 348  Maximum: 1073
-47 ppm Crystal too slow, Tack: 355  Maximum: 1003
-46 ppm Crystal too slow, Tack: 363  Maximum: 902
-45 ppm Crystal too slow, Tack: 371  Maximum: 1101
-44 ppm Crystal too slow, Tack: 379  Maximum: 1140
-43 ppm Crystal too slow, Tack: 388  Maximum: 911
-42 ppm Crystal too slow, Tack: 397  Maximum: 884
-41 ppm Crystal too slow, Tack: 407  Maximum: 915
-40 ppm Crystal too slow, Tack: 417  Maximum: 1047
-39 ppm Crystal too slow, Tack: 428  Maximum: 1056
-38 ppm Crystal too slow, Tack: 439  Maximum: 749
-37 ppm Crystal too slow, Tack: 451  Maximum: 867
-36 ppm Crystal too slow, Tack: 463  Maximum: 1015
-35 ppm Crystal too slow, Tack: 477  Maximum: 837
-34 ppm Crystal too slow, Tack: 491  Maximum: 1094
-33 ppm Crystal too slow, Tack: 506  Maximum: 779
-32 ppm Crystal too slow, Tack: 521  Maximum: 787
-31 ppm Crystal too slow, Tack: 538  Maximum: 741
-30 ppm Crystal too slow, Tack: 556  Maximum: 961
-29 ppm Crystal too slow, Tack: 575  Maximum: 821
-28 ppm Crystal too slow, Tack: 596  Maximum: 768
-27 ppm Crystal too slow, Tack: 618  Maximum: 1080
-26 ppm Crystal too slow, Tack: 642  Maximum: 1036
-25 ppm Crystal too slow, Tack: 667  Maximum: 1032
-24 ppm Crystal too slow, Tack: 695  Maximum: 1001
-23 ppm Crystal too slow, Tack: 725  Maximum: 1038
-22 ppm Crystal too slow, Tack: 758  Maximum: 939
-21 ppm Crystal too slow, Tack: 794  Maximum: 981
-20 ppm Crystal too slow, Tack: 834  Maximum: 1142
-19 ppm Crystal too slow, Tack: 878  Maximum: 1515
-18 ppm Crystal too slow, Tack: 926  Maximum: 1011
-17 ppm Crystal too slow, Tack: 981  Maximum: 893
-16 ppm Crystal too slow, Tack: 1042  Maximum: 2248
-15 ppm Crystal too slow, Tack: 1112  Maximum: 1148
-14 ppm Crystal too slow, Tack: 1191  Maximum: 1278
-13 ppm Crystal too slow, Tack: 1283  Maximum: 1767
-12 ppm Crystal too slow, Tack: 1389  Maximum: 1023
-11 ppm Crystal too slow, Tack: 1516  Maximum: 907
-10 ppm Crystal too slow, Tack: 1667  Maximum: 852
-9 ppm Crystal too slow, Tack: 1852  Maximum: 909
-8 ppm Crystal too slow, Tack: 2084  Maximum: 829
-7 ppm Crystal too slow, Tack: 2381  Maximum: 886
-6 ppm Crystal too slow, Tack: 2778  Maximum: 807
-5 ppm Crystal too slow, Tack: 3334  Maximum: 1057
-4 ppm Crystal too slow, Tack: 4167  Maximum: 1179
-3 ppm Crystal too slow, Tack: 5556  Maximum: 910
-2 ppm Crystal too slow, Tack: 8334  Maximum: 1083
-1 ppm Crystal too slow, Tack: 16667  Maximum: 1172
0 ppm Crystal almost perfect Maximum: 1384
1 ppm Crystal too fast, Tack: 16670  Maximum: 1189
2 ppm Crystal too fast, Tack: 8334  Maximum: 1533
3 ppm Crystal too fast, Tack: 5555  Maximum: 2041
4 ppm Crystal too fast, Tack: 4166  Maximum: 2485
5 ppm Crystal too fast, Tack: 3333  Maximum: 2401
6 ppm Crystal too fast, Tack: 2777  Maximum: 2941
7 ppm Crystal too fast, Tack: 2381  Maximum: 3454
8 ppm Crystal too fast, Tack: 2083  Maximum: 3586
9 ppm Crystal too fast, Tack: 1851  Maximum: 3606
10 ppm Crystal too fast, Tack: 1666  Maximum: 3068
11 ppm Crystal too fast, Tack: 1515  Maximum: 2573
12 ppm Crystal too fast, Tack: 1388  Maximum: 2254
13 ppm Crystal too fast, Tack: 1282  Maximum: 1849
14 ppm Crystal too fast, Tack: 1190  Maximum: 1290
15 ppm Crystal too fast, Tack: 1111  Maximum: 1242
16 ppm Crystal too fast, Tack: 1041  Maximum: 1246
17 ppm Crystal too fast, Tack: 980  Maximum: 1131
18 ppm Crystal too fast, Tack: 925  Maximum: 1121
19 ppm Crystal too fast, Tack: 877  Maximum: 1164
20 ppm Crystal too fast, Tack: 833  Maximum: 1122
21 ppm Crystal too fast, Tack: 793  Maximum: 1260
22 ppm Crystal too fast, Tack: 757  Maximum: 1144
23 ppm Crystal too fast, Tack: 724  Maximum: 947
24 ppm Crystal too fast, Tack: 694  Maximum: 1237
25 ppm Crystal too fast, Tack: 666  Maximum: 1550
26 ppm Crystal too fast, Tack: 641  Maximum: 1170
27 ppm Crystal too fast, Tack: 617  Maximum: 1201
28 ppm Crystal too fast, Tack: 595  Maximum: 964
29 ppm Crystal too fast, Tack: 574  Maximum: 2205
30 ppm Crystal too fast, Tack: 555  Maximum: 1049
31 ppm Crystal too fast, Tack: 537  Maximum: 1078
32 ppm Crystal too fast, Tack: 520  Maximum: 1160
33 ppm Crystal too fast, Tack: 505  Maximum: 1215
34 ppm Crystal too fast, Tack: 490  Maximum: 1071
35 ppm Crystal too fast, Tack: 476  Maximum: 1136
36 ppm Crystal too fast, Tack: 462  Maximum: 1160
37 ppm Crystal too fast, Tack: 450  Maximum: 1393
38 ppm Crystal too fast, Tack: 438  Maximum: 952
39 ppm Crystal too fast, Tack: 427  Maximum: 933
40 ppm Crystal too fast, Tack: 416  Maximum: 1051
41 ppm Crystal too fast, Tack: 406  Maximum: 1288
42 ppm Crystal too fast, Tack: 396  Maximum: 1182
43 ppm Crystal too fast, Tack: 387  Maximum: 878
44 ppm Crystal too fast, Tack: 378  Maximum: 981
45 ppm Crystal too fast, Tack: 370  Maximum: 1446
46 ppm Crystal too fast, Tack: 362  Maximum: 985
47 ppm Crystal too fast, Tack: 354  Maximum: 1035
48 ppm Crystal too fast, Tack: 347  Maximum: 937
49 ppm Crystal too fast, Tack: 340  Maximum: 961
50 ppm Crystal too fast, Tack: 333  Maximum: 1002
51 ppm Crystal too fast, Tack: 326  Maximum: 1057
52 ppm Crystal too fast, Tack: 320  Maximum: 1086
53 ppm Crystal too fast, Tack: 314  Maximum: 1028
54 ppm Crystal too fast, Tack: 308  Maximum: 990
55 ppm Crystal too fast, Tack: 303  Maximum: 1206
56 ppm Crystal too fast, Tack: 297  Maximum: 1182
57 ppm Crystal too fast, Tack: 292  Maximum: 1050
58 ppm Crystal too fast, Tack: 287  Maximum: 1274
59 ppm Crystal too fast, Tack: 282  Maximum: 1128
60 ppm Crystal too fast, Tack: 277  Maximum: 1231
61 ppm Crystal too fast, Tack: 273  Maximum: 991
62 ppm Crystal too fast, Tack: 268  Maximum: 1216
63 ppm Crystal too fast, Tack: 264  Maximum: 1749
64 ppm Crystal too fast, Tack: 260  Maximum: 1409
65 ppm Crystal too fast, Tack: 256  Maximum: 1018
66 ppm Crystal too fast, Tack: 252  Maximum: 1510
67 ppm Crystal too fast, Tack: 248  Maximum: 1767
68 ppm Crystal too fast, Tack: 245  Maximum: 1924
69 ppm Crystal too fast, Tack: 241  Maximum: 1167
70 ppm Crystal too fast, Tack: 238  Maximum: 1893
71 ppm Crystal too fast, Tack: 234  Maximum: 4063
72 ppm Crystal too fast, Tack: 231  Maximum: 5096
73 ppm Crystal too fast, Tack: 228  Maximum: 5754
74 ppm Crystal too fast, Tack: 225  Maximum: 5692
75 ppm Crystal too fast, Tack: 222  Maximum: 4651
76 ppm Crystal too fast, Tack: 219  Maximum: 2854
77 ppm Crystal too fast, Tack: 216  Maximum: 1133
78 ppm Crystal too fast, Tack: 213  Maximum: 1668
79 ppm Crystal too fast, Tack: 210  Maximum: 1346
80 ppm Crystal too fast, Tack: 208  Maximum: 1416
81 ppm Crystal too fast, Tack: 205  Maximum: 896
82 ppm Crystal too fast, Tack: 203  Maximum: 1205
83 ppm Crystal too fast, Tack: 200  Maximum: 1302
84 ppm Crystal too fast, Tack: 198  Maximum: 810
85 ppm Crystal too fast, Tack: 196  Maximum: 1015
86 ppm Crystal too fast, Tack: 193  Maximum: 2043
87 ppm Crystal too fast, Tack: 191  Maximum: 1039
88 ppm Crystal too fast, Tack: 189  Maximum: 1498
89 ppm Crystal too fast, Tack: 187  Maximum: 824
90 ppm Crystal too fast, Tack: 185  Maximum: 1039
91 ppm Crystal too fast, Tack: 183  Maximum: 1012
92 ppm Crystal too fast, Tack: 181  Maximum: 900
93 ppm Crystal too fast, Tack: 179  Maximum: 1164
94 ppm Crystal too fast, Tack: 177  Maximum: 868
95 ppm Crystal too fast, Tack: 175  Maximum: 1346
96 ppm Crystal too fast, Tack: 173  Maximum: 996
97 ppm Crystal too fast, Tack: 171  Maximum: 950
98 ppm Crystal too fast, Tack: 170  Maximum: 2321
99 ppm Crystal too fast, Tack: 168  Maximum: 1129
100 ppm Crystal too fast, Tack: 166  Maximum: 1232
 
