A simple script for calculating Loran lines:

<code>

#!/usr/bin/python # modify this for M$ or other, not tested

# two GRIs wanted here
GRI1 = 7499
GRI2 = 6731

# true period
T1 = GRI1 * 1e-5
T2 = GRI2 * 1e-5

# don't want to go to infinity
max = 5000

# main loop

  deltaF = i / (2*T1) # 1st gri
  f1 = 100000 - deltaF # below rattling only, otherwise +
  print f1
  deltaF = i / (2*T2) # 2nd gri
  f2 = 100000 - deltaF
  print f2
</code>

Correct?