I think the frequency is determined by the first stage, with the BB105 and
the 25 mm long wire.
The coil L is in the second stage which is an RF amplifier and shouldn't
change the frequency (or am I mistaken?).
The silver or silvered wire is puzzling. I guess the precise 25 mm length
is to make an inductor, and the designer must have thought that it needs
very low RF (skin effect) resistance, to get large Q. You would not see
that effect unless you include skin effect resistance in your simulation.
Andy
