[Boatanchors] (Slightly OT) A question concerning theory behind a certain antenna matcher (Kenwood AT120)

[Rob Atkinson]

it's built the way it is partly to save money.  it's cheaper to
manufacture a design around a pair of air variables than it is to use
a decent roller inductor.   fixed taps and caps that are switched are
less expensive and also more reliable if the switch is good.  If  you
think about sourcing parts in terms of buying several hundred or a
thousand of each you start to see what drives component choices and
high power RF tuner and amp designs for hams.   the engineer has to
come up with a design that does something.  Then he has to come up
with a way that uses parts that are available in large quantities
cheap.  That is usually what's behind designs in ham hear nowadays
that seem weird or odd.  MFJ does have an edge wound roller inductor;
they sell it for $140.

73

Rob
K5UJ