Winding them with bare copper wire:
* They won’t get an even distributed spacing
* Handling them, changes their inductance
* They partly uncoil again, as you let go
Nothing is controllable.
Until you take duct tape, alias ‘Panzer-tape’, alias Gaffa and what else you call it.
Take a random object with the desired diameter.
Roll the ‘duck’ tape backwards, with the sticky side out. One round, and a little overlap.
No, this isn’t easy. Never mind, as good as possible.
Use insulated wire. This secures even spacing!
Roll what you need of windings.
Make the windings tight to the object under, but not too much either, or it won’t get off later as one.
Later on, when tested and approved, and at own will, varnish the windings to avoid humidity in the air between the windings to change the inductance due to parasitic capacitance.
Maybe put on too many windings first, and trim as needed, for those unsure of the final results.
