Hi all,
Please forgive my failing memory, but was not
"efficiency modulation" (in the time before SSB)
taken to it's extreme with 'clamp tube' operation of
tetrodes e.g. 807s?
As a young (16 year-old) ham, I tried clamp-tube
modulation because I couldn't afford a big
modulation transformer etc.
It got a bad rep because AM ops didn't switch off
their receiver's AGC - in those days, they were either
CW or Phone ops (has anything changed?).
In the '60's, a Marconi "Kestrel" marine transmitter
(two 6146s) used a modified form of "controlled
carrier" on AM that worked very well - some of the
plate modulator output was rectified and used to
supplement a lowered standing screen voltage.
I don't know who copied whom, but there was a
similar circuit published in CQ Magazine around the
same time.<G>
73, Ken ZL1AIH
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