Re: LTSpice simulation of uBitx Power Amp

Jerry Gaffke

I suppose.
The LTSpice model of the IRF510 does assume worst case, perhaps that is part of it.
But the WA2EBY model is off from the performance reported in the QST article by more than I would expect when operating at 30mhz.
And the uBitx models pretty close to the performance we actually get.

Regardless, looks like we'd do well to hack the uBitx to use something closer to the WA2EBY circuit.
And if that doesn't give the required performance at 30mhz, then drive the IRF510's from a lower impedance source.
LTSpice is whispering to me that if driven hard enough, the IRF510's will do 30W at 30mhz.

Jerry, KE7ER

On Mon, Feb 5, 2018 at 10:47 am, Diver Martin wrote:
> Let me know if anybody figures out why my model of the WA2EBY amp shows the output to be so much lower at 30mhz
To quote George E.P. Box, "All models are wrong, but some are useful."
Spice models are just that, models.  They're rarely right.  But they can tell you useful things about some of the mechanics of what's going on inside the system.

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