Hello,
Rik Strobbe wrote:
I am using a 'G3YXM' PA, slightly modified from the original. Main changes
are a pair of IRFP350's on each side of the push-pull (running at 56V) and
an extra LC section in the LPF.
With 9.2A draincurrent (= 515W input) I get 2.95A RF current into my 52 Ohm
dummyload (= 452W output). That means 87.8% efficiency.
Seems to be within the range of this famous 'Class E'.
It's a classical "class-D" design, i.e. a switched
pp-amplifier reaching very high efficiency but much more
complicated than class-E. Running class-D means that most
dissipation occurs at switching time. Class-E is able to
avoid dissipation even at switching. The key is to load an
amplifier capacitively such that (MosFet) Ud *and* dUd/dt at
switchig time are both zero (soft landing). Theoretically
(!) you will have no dissipation at all...
54°16'N / 10°04'E, JO54ag
73 es gl de Peter, DF3LP
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