[AMRadio] AM Transmitter Advice??
Mike Sawyer
w3slk at uplink.net
Wed Feb 15 18:48:52 EST 2006
Don, K4KYV said: Sometime in the late 1920's, it occurred to someone that
class-B linear
amplification would work just as well for audio as for rf, and the class-B
audio amplifier was developed. The unusual thing about this setup was the
large audio transformer required. Many rf linears were single-ended, and
depended on the fiywheel effect of the rf tank circuit to supply the missing
half of the sinewave output. With class-B audio amplification, the tubes
have to be in pushpull in order to reproduce both halves of the sinewave.
Thus the well-known "class B modulator" came into being.
Interesting that you mention this Don. I just read where it was Art Collins
and his group that came up with the idea of using Class B push-pull audio
for Class C rf amplifier. I'm not a Collins aficionado but Joe, N3IBX gave
me the book, "The First Fifty Years of Collins" to read and I found it very
good reading. There was some self-promoting in there but I was mildly
surprised when I learned Collins did discover the Class B P-P plate
modulation scheme.
Mod-U-Lator,
Mike(y)
W3SLK
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