[Amps] Class A fo AM

[zl1aih at ihug.co.nz]

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