In the last few days I have reread chapter 13-The Itasca and Howland Island-of Elgin Long's book. I also reread some of chapter 14-The Search for Earhart. I wanted to see if by what Long said there could have been a last minute south bound run that could have ended with a landing at Gardner Island. Earhart made a broadcast at 0803 ISTGardner Island?(Itasca Ship Time) that he said "was very loud and sounded even closer than before." So, Earhart was still getting closer to Howland Island. Her next broadcast was at 0843 IST. Long states "She was loud, at the same strength she had been an hour earlier at 0742 IST". However, Long shortly thereafter says "For the first time, her signal was not quite as strong as the preceding signal had been.". Was Earhart on her way southward toward Gardner Island? and getting further away from Howland Island? Nothing was heard from Earhart again.
Would the 40 minutes between 0803 IST and 0843 IST be enough to result in a landing at Gardner Island? One could add some additional minutes to these 40 minutes but I don't think it would be logical to go beyond that. How about 20 minutes more for a total of one hour flying time to Gardner Island. At 0742 IST Earhart said she had only one hour of fuel left. That one hour ended at the time of her last broadcast at 0843 IST.
One could work one's way back from Gardner Island and find a starting point or points for Earhart's run to a Gardner Island landing utilizing a projected aircraft speed she may have used in the run to Gardner.
Concerning whether or not a possible in air announcement by Earhart was made announcing she was going to land on an island, it would be interesting to conduct a test of in air radio reception by placing like equipment at Howland Island and in a plane south of Howland Island(identical equipment would be ideal) at the times and date, July 2 give or take a few days, and remake her known announcements along with additional testing after her last 0843 IST broadcast to see what would be learned. Or, would expert testimony suffice in lieu of such a test?