Tom says
>Linear PA's, with their longer conduction angles, generate much less
>harmonic energy than the old class C PA's. Class AB PA's make
>very poor harmonic generators, that's why doublers and triplers are
>all operated in low conduction angle modes (like class C).
Sorry Tom, I don't agree. In a class B stage, (and the same pretty well
applies to a Class AB stage) the second harmonic component of plate
current is about 6dB down on the fundamental - see Pappenfus et al.,
p164 et seq. In a Class C stage, the second harmonic is slightly lower,
while (assuming a 120 degree conduction angle) the third harmonic is
rather higher than at 180 degree conduction - see Termans 'Radio
Engineering' , 3rd edition, 3rd impression, sec 7-5, p. 394 et seq. A
picky and pedantic point perhaps, but one which could easily lead to
misunderstandings downstream. Having said that, I had a tx at one time
that I could use in Class C on 15 metres back in the days of TV on 42MHz
here, but I couldn't get away with it in AB1.
73
Peter G3RZP
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