Define f, Q and "very small" Generally like Xtals it is wiser to use series resonance for VHF or > 30 MHz due to the sensitivity of stray capacitance in parallel loops. Using an "RLC monograph" is an intuitive and quick way to do many tank circuit designs without a calculator. Parallel Q is the R ratio above the intersection of LC&f. While series Q is the R ratio below that impedance.
Another tool is free "Saturn PCB Design" windows app on the planar Inductor tab> circular.
The LCR meter needs to read 0 nH when shorted and xx nH with connected to coil. at max f.
10 nH is about 15 mm of straight wire and so you cannot do this on a breadboard. The collector should not have any significant inductance, meaning a couple of mm SMD Rc resistor to an SMD decoupling cap between Vcc and gnd. This would shift the phase of the oscillation, reduce the gain and probably stop oscillating.
I'd guess that it is not R2 directly, but changing the biasing changes the voltages on the transistor junctions and causing a "varicap" type effect.
(It's a seriously weird circuit!)
The circuit is basically a two-transistor Schmitt Trigger circuit with a resonant LC tank as load for the first transistor, but I guess it looks weird because not too many people build Schmitt Triggers from discrete components anymore.
The circuit is basically a two-transistor Schmitt Trigger circuit with a resonant LC tank as load for the first transistor, but I guess it looks weird because not too many people build Schmitt Triggers from discrete components anymore.