What if some waypoints fall outside the ASF tables?
If you have waypoints falling in areas where no ASF tables exist, then you will see an increased error in the conversions. You will also see a note at the top of the screen indication that no ASF table was found (for some waypoints). If the ASFs for that area are, for example, 2 microseconds and the Loran line spacing is 10 microseconds per mile, then you will have an error of 1/5 mile if 0 is used for the ASFs. In this case, you can use the single ASF per file method of applying ASFs and that will eliminate most of the error. Here, you set the ASFs for the whole file area. You can use the nearest good ASF from the tables or you can derrive the ASFs by calibrating on some known reference points in the area. It is good practice to keep these waypoints in a separate file from those that fall in areas where the calibrated ASF tables exist. The ASF examiner will show you what tables do exist (or you can check the graphic links below), so you can make that determination. Also, the program s
