First get youreslf 4 identical coils (as much as they can be identical), a nice power source and a function generator. If you have any experience with electrics you can even make your own fun.gen. and power supply. Arange them in such a way they form a cross +.

(1).....................(2)
.....B................... B
.....|.................../
A--+--A'......A --/--A'
.....|................./
.....B'..............B'

(Dots are empty space, instead of space character since this forum removes all empty spaces from ascii art.)

Then experiment with various setups of coils and frequencies. Pic 1 and 2 have diferent angle between coil axes A-A' and B-B'. All you must know is that the magnetic fileds generated by coils must support each other, they should not be opossing. That means if coil A is turned N-S, then A' must be N-S, and you get N-(S|N)-S coupling. This can be done by coil winding (or turning the coil around) or with power supply. Remeber that you need two PAIRS united as one (ie. four coils with common void point; (+) in pic 1, (S|N)). That's what I understand from the Kovac-Grotz-Binder article and from reading W.R. Let me know when you strike oil.

Kind regards.

ps. I've got coils and power supply. I hope I can make my fun.gen. soon from old soundblaster card and old PC.

Please comment, any thoughts on this are much apreciated.