The "100-miles out" comment is suspected to have been an estimate by the radio Operator, not something said by AE. See Note 3 at
http://tighar.org/wiki/Transmissions_heard_from_NR16020 If so, then it can't be used for our navigation analysis, other than to assume AE was at her closest approach to the island.
Also, in discussions about loop antennae, keep in mind that they have frequency limits. AE seemed to have a fuzzy understanding of how to use the antenna to obtain a minimum, but specified a frequency that would not work with that antenna.
dit dah dit dah dit dah dit dah dit dah dit dah dit dah dit dah dit dah dit dah dit dah dit dah dit dah dit dah dit dah dit dah dit dah dit dah dit dah
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240
Can you find the minimum? Neither could she. Her loop antenna was only sensitive to different directions much lower frequencies.