This is your experiment, and I do not wish to distract you, but remember our conversations on LCR Resonance and how this can bring on Magnetic Resonance, we saw this in The Mr Preva Experiment.
With few turns, the Distributed Capacitance will be low, Resonance may be in the several hundreds of KHz.
Perhaps adding some Capacitance, to bring down the Resonant Frequency.
Amplitudes always increase at Resonance.
Also, my recent reminder posts on the Sawtooth Wave, its worth studing and understanding why, I have covered several times why we see this wave.
As we continue to learn, more questions arise, but I ask, please be patient. We have covered a lot, and I hope by doing a full review it makes more sense now, that many many questions have been answered already.
Our small cheap and extremely simple experiments are already showing very interesting results.