The ship listened for AE’s answer on 3,105, 6,210, and 500 kilocycles.
The message was not acknowledged.
“We are running north and south,” at 8:45 A.M. had been Amelia Earhart’s last words.
Until ten o’clock on that morning of July 1 the Itasca continued to call. The operators transmitted on 3,105 and 7,500, and listened on 3,105, 6,210, and 500, and also on 500 of the direction finder.
Nothing more was heard from the Electra.
The decision of the Itasca’s crew was obvious and unanimous: Amelia Earhart was having radio receiver trouble.
Questions abounded. How account for her last report: “We are in a line of position 157-337”? What was the geographical point of reference for the line of position? Did she get a bearing from Howland? Where was she when she made the report?
The answers lay partially in several alternatives: the Electra’s loop antenna, or radio; the stars before dawn, or the early-morning sun.
The loop antenna, one of the plane’s direction finders, had a low-frequency limit of 200–1,500 kilocycles and a high-frequency limit of 2,400–4,800 kilocycles; therefore, it could not receive the Itasca’s homing signal from 7,500 kilocycles, but it could receive the one from 500 kilocycles. If the line of position 157-337 were determined from 500 kilocycles, then the all-important point of reference from which it was drawn had to be understood as Howland or the Itasca.
Obviously, AE knew her line of position, but she did not know where she was north or south on the line. This fact accounts for her “We are running north and south.” If she had known her exact position, she would not have conducted the search pattern for the island, nor would she have asked the Itasca to take bearings on her.