How to understand “resonance between the coils”?

Sure. A coil has a particular resonance of its own. However, in this context, we are talking about resonance where the energy of the transmission from the transmitter box energizes the coil of the receiver with sufficient energy to be worth something.

Simply putting power into the transmitter coil is not enough. When you hit certain frequencies, the coil of the receiver will energize with significance — where the two are in resonance with each other.

The frequency at which this happens is governed not by the resonance of the coil itself, but by the distance between the coils, additional objects that are between the coils, and objects on the coils.

So I was referring to the frequency at which the receiver coil is energized enough to produce sufficient current to light the link cable light. Anything else is moot.

For more details, please check this link:
https://www.facebook.com/groups/spooky2scalar/posts/940161959890696/