But Chater explained that the reason that they could not hear the plane on 6210 for several hours after takeoff was due to "local interference" ...
Chater gave an explanation that made sense to him.
I find it hard to imagine that "local interference" overrode the eight scheduled transmission times that were not heard.
I understand that this is speculative.
If, instead, she flew for almost three more hours to Gardner then it is beyond credulity that she would not have had the time, the ability and the imperative to transmit "in the blind" on each of her frequencies informing Itasca and the whole world of her intentions.
It's not beyond my credulity. AE did lots of things that are, in retrospect, incredible. It strains my credulity that she would fail to master the radio system on which her life depended, and yet, that
seems to have been the choice she made. When push came to shove, she did not know how to transmit a signal on the right frequency for the right length of time for the
Itasca to get a bearing, nor did she know what was the best frequency for her to use to take a bearing on. She didn't switch between 3105 and 6210 during the morning hours; in my imaginative reconstruction of what she "would have done," she didn't switch between 3105 and 6210 after announcing her plan to go to her daytime frequency.
I've got to add the
failed RDF test in Lae to my list of indicators of how irrationally Earhart behaved. This was the one leg of the flight where radio direction finding was essential; she tested her equipment; she and the equipment flunked the test; she explained away the results; the next time she tried to use the equipment, she flunked the test again.