Begin hand wiring the wire in the middle of its
own length, winding the two wires in opposite
directions around the core and carefully crossing
the wires on the same opposite points each time
around.
The book case was based on a 9" long iron core.
The description calls the results an Energy Sink.
Namely, current fead into it just disappears,
causing NO radiation or heat. It is also rumoured
to have zero impedance (???), among many other
strange RF characteristics.
Other things it mentions is that minor variations
in the construction change in how it operates.
Although still in unusual ways.
The section in the book goes on for several pages.
Supposedly there was a technical article published
in 1980 by Gaston Burridge, called "The Smith Coil".
This was in Volume 35, Ed.No.5 of "Psychic Observer"
magazine (!).
Sounds like a simple and bizarre area to research!
Bob