PI coil cable - triboelectric noise - problems - solutions?

[Ferric Toes]

You mention one thing that has been difficult for me to bring together as one.
That would be the electrical & mechanical properties.
The cables I have tried so far suck at either one or the other. This perspective is for much flexed pinpointer cables.

As to the ferrite rods:
1.) Yep, my testing indicates that too. There's a nice chart somewhere with diameter/length ratios etc. showing this
2.) This has me laughing -memories- I once had a singing ferrite - the look on my face. Sounded quite good actually.
2a.) One ferrite I drove way to hard, forgetting the limiting resistor, violent ferrite noise, panic switch off.
This ferrite hasn't been "good" to use ever since. Something must have changed in the structure or so.
3.) May have to do with saturation and/or biasing as far as I've understood so far.
4.) Work in progress ...

Looking forward to further posts. May your re-organisation of life flow with ease.

The mechanical ringing (singing) also results in an electrical waveform which looks the same as a undamped inductance. The difference is that you cannot get rid of it with a damping resistor. You can apply damping to the ferrite rod by encapsulating it in a 'soft' polyurethane resin. You can also identify it by squeezing the rod between fingertips.

I can quarantine myself in my workshop if need be.

Eric.