John Smith wrote:
However, if
anyone has a view to the contrary, I would be interested in the
specifics ...

In a coil wound on an iron-core toroid, do you believe
the flux follows the wire in the coil and ignores the
iron in the toroid?

Coupling is, of course, not nearly that good in an air-
core coil but coupling exists nonetheless. Some of
the current generated in a coil is through the air-core
transformer action between coils.
--
73, Cecil http://www.w5dxp.com