Dave Heil wrote:

An article on the
various voice modes mentions Fessenden's 1906 amplitude modulation feat.

Make that "feats", Dave, 'cause RF did a number of them.

The one most remembered is his Christmas Eve 1906 "broadcast" of voice
and music, which was received by both land stations and ships at sea.

That broadcast was repeated on New Year's Eve.100 years ago tonight!

But RF also had 2 way transatlantic voice communication working even
earlier.

73 de Jim, N2EY