On the Transmission heard from 16020 page:
17:47 GMT : Howland Island states: "Picked up Earhart (using long antenna, S3, hardly any carrier. Seemed overmodulated. Switched over to loop for Bearing, S1 - 0. She stopped Transmission). Bearing Nil. 3105."
This was 5 minutes after her 17:42 GMT transmission where she stated that she was 200 Miles out. The units are presumed to be nautical miles for the report.
Because Howland was fiddling with the radio, switching from voice to the DF, they probably missed what was said. I believe the Itasca log states it was "Working Howland, Passing on the dope" around this time so they probably missed this transmission as well.
What is interesting, if my calculations are correct, the sun would have just peaked over the horizon if the the Electra had not yet descended from 10,000ft. From what I understand, there were recommendations to start the descent at about 150NM out, so it would make sense if they were still at 10,000ft.
Running the numbers for sunrise at a 1,000ft altitude, this event would have not happened until approximately 17:51 GMT.
If she was trying to report seeing the sunrise, this would have validated that they were accurately tracking their speed and distances at least longitudinally as they made their approach to Howland.
It is really unfortunate that they decided to fiddle with the radio on Howland right at that moment as we will never know what she was actually attempting to communicate.
I do however think it is a plausible explanation as to why she popped in on the radio after her 17:42 GMT report.