Please be aware that my above instructions and explanations refer ONLY to newer Etherwaves, starting with board revision 211C AND the updated circuit where the coils have hexagonal slugs.
The 288300Hz above are an average secure value with which the Etherwave will have a reasonable pitch field, but much depends on the components' tolerances.
With earlier versions, things are different.
I have to add a word about the "magical" wire: It forms an adjustable capacitor together with the grounded foil below. Bending it upwards will reduce the capacitance and thus stretch the "natural" distance somewhat. Bending it downwards will add some fractions of a picoFarad and slightly compress the "higher" pitch field. Each bending requires a slight re-adjustment of L6 in order to re-center the pitch knob.
The 288300Hz above are an average secure value with which the Etherwave will have a reasonable pitch field, but much depends on the components' tolerances.
With earlier versions, things are different.
I have to add a word about the "magical" wire: It forms an adjustable capacitor together with the grounded foil below. Bending it upwards will reduce the capacitance and thus stretch the "natural" distance somewhat. Bending it downwards will add some fractions of a picoFarad and slightly compress the "higher" pitch field. Each bending requires a slight re-adjustment of L6 in order to re-center the pitch knob.