I am looking for documentation describing the coupling of inductors which a= re physically separated, and oriented at 90 degrees, yet as Q is increased,= suddenly become coupled such that tuning one LC pair tunes the other pair. I suspect this is either in the domain of wireless charging, or it's buried= back in something done between 1920 and 1940. Any ideas? -- David VanHorn Lead Hardware Engineer Backcountry Access, Inc. 2820 Wilderness Pl, Unit H Boulder, CO 80301 USA phone: 303-417-1345 x110 email: david.vanhorn@backcountryaccess.com --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .