starman wrote in :

BTW- The loop antenna on top of Earhart's plane was for direction
finding a radio signal from it's transmitter source. This was one way
they used to navigate in those days. Earhart left behind the long
trailing wire antenna that could have been used to receive the MW
(500-Khz) signal because she wanted to reduce the aircraft weight for
the long flight to Howland island. The HF (shortwave) frequencies were
3105 and 6210-Khz.

SR wrote:

PBS had a documentary on the life of Emailia Earhart. It showed the
airplane she used. The airplane had a small loop antenna above the
head of the airplane. And I believe a saw a 2-3 vertical antenna
behind the loop antenna.

Does anyone have any information on the types of radios she was
using? Or the radio bands she was transmitting on?

PBS mention that she left behind a 500 khz wire antenna. Somehow she
did make radio contact with a US ship in the Pacific before
disappearing.

Some time ago I ran across a web site maintained by folks who apply
archaeological methods to an ongoing search of the presumed crash site.
They provide an interesting collection of material on the radio
transmissions heard from Earhart's plane and they're well worth perusing
if you're interested in frequencies used.

http://www.tighar.org/Projects/Earhart/Bulletins/37
_ItascaLogs/Itascalog.html

I believe that somewhere among these pages is a description of the rigs
and antenna system on the plane.

There are also some speculations that portions of these and other logs
may be inaccurate:

http://www.usni.org/NavalHistory/Articles00/nhriley.htm

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