I recently built a 100W HF amplifier by modifying existing designs.
Now I'd like to build an automatic antenna tuner. Where can I find some
good articles / web sites on theory, practical design, and tuning
algorithms for the switching circuit. Has anyone published all the
details including source code.

QST published a (two-part?) article on an "Easy Tuner" design a couple
of years ago. As I recall it's a microprocessor-controlled tuner of
the T configuration, with a switched tapped shunt inductor, and two
air-variable series capacitors driven by small motors.

I believe that source code was available.

I suspect that most of the ATU-control code out there is proprietary,
and that which isn't is likely at least somewhat specific to a
particular ATU design. Designs using motor-driven capacitors are
going to be at least somewhat different from those which use
relay-switched capacitor sets.

--
Dave Platt AE6EO
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