[Amps] Russian power L-coupler

[Angel Vilaseca]

Hi,

On Ebay, I saw some russian L-couplers for sale.

They are made of two coils, both wound on a virtual sphere. One of the 
coils is slightly smaller and placed within the larger one. The inner 
coil can be rotated so the turns are from parallel to the other's (max 
coupling), and all the way to  perpendicular (min coupling). 

Has anyone tried to use these couplers in a tank circuit? Both coils 
could be tuned by variable capacitors and the coupling between the two 
coils would then be optimized for maximum power output.

Vy 73 de Angel Vilaseca HB9SLV