"Bret Ludwig" ) writes:
Plate modulation is not a way of producing SSB. The SSB signal must be
amplified linearly, and generated at low level. FM, I believe, not only
can but benefits from being run through a Class C stage. The idea with
plate modulation was that the RF path was CW all the way to the finals,
and the audio directly modulated the final amp. The modulated signal
then had to be handled only in a linear fashion, but that was at the rx
end-the last stage in the tx being, obviously, the final.

Well actually, you could do phasing at high levels. And depending on
the high level balanced modulator, it just might be plate modulation.

You put two high level balanced modulators at the output of what
amounts to a CW transmitter. The balanced modulators knock out the carrier.
Then you use the phasing method to knock out the unwanted sideband.

No commercial rig did it this way. I'm not so sure any homebrew rig
did it. But it is within the realm of possibility. Certainly, there
were a fair number of articles for high level balanced modulators so
you could take an existing rig and output DSBsc. It was far easier
to add such a stage, or modify the output stage of an existing transmitter
to make it a balanced modulator, than to put in a low level balanced
modulator and then linearize the rest of the transmitter.

Michael VE2BVW

The gizmo we are looking at seems to be a simple mod xfmr placed in
the plate supply to the 6146s in the tx. An audio amp such as a stereo
or guitar amp hooks to it and the mic goes to a preamp. In fact my
guess is back then a guitar amp was exactly what was most used.