>
> NO! NEVER!
Well, I heartily disagree.
>
> The overall efficiency of the high level plate modulated rig
> is better than any linear so there's less heat in the room
> for the same power output.
You're forgetting all of the other stuff, modulators, audio drivers, RF
drivers, whatever. The Class C finals, are not the only thing generating a
bit of heat.
> It takes lots of modifications to the DX-60 to produce AM
> that can't be distinguished from the high level modulated rig
> because the screen modulation used controlled carrier and so
> shifted the carrier level to match the modulation level and
> that shows on the receiver S-meter. At least it did 30 to 50
> years ago...
That was then. This is now. There are many DX-60's on the air today with
amps, modifed quite easily to produce an outstanding AM signal, with none of
the old controlled carrier bugaboos.
> tank). These efficiencies you can only improve on with lots
> of distortion from the AM linear.
It doesn't really matter much about the difference in efficiency. A linear
amp, IF PROPERLY ADJUSTED (the key phrase) produces an excellent low
distortion signal with low level AM drive, from a DX-60, Orion, FT-102, pick
one.
I have yet to have anyone on the other end able to tell whether I've heated
up the GK500B, Champ 300 or am running the Orion (with the same audio chain
driving all of the radios).
Grant/NQ5T
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