In article , Leo
writes:

I wonder if W1AW pre-records their CW material in audio format, then
broadcasts it as a modulated SSB signal - would that not stretch the
signal bandwidth out considerably?

Yes, but that's not how it's done.

Anyone know if this might be the case?

Here's how it was when I visited in 1993:

The W1AW main transmitters are Harris transceivers and amplifiers, all computer
controlled from a master console in the little building out in front of Hq.
Bulletin and code practice texts are sent over the network from the
headquarters building and the local computer keys all the rigs simultaneously.
(Text-to-Morse conversion is done in the local computer).

Of course a faulty command from the computer, a bad cable or problem in one of
the "professional grade" rigs could wreak all kinds of havoc.

But they don't feed audio into the rigs for Morse or RTTY.

73 de Jim, N2EY