Finally got around to ordering the NFC coil antenna test board. Should be here next week. I’ll post the analysis after they come in.
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Boards came in. Results varied, but at least it provided some valuable data. The coil parameters are written on the board silkscreen. All of the copper weights were 1oz/ft^2.
Here are the results of my measurements with a quality LCR meter.
2.545μH coil: (L = 2.68μH)(R = 1.4Ω)(Q = 0.013)
2.834μH coil: (L = 2.11μH)(R = 1.2Ω)(Q = 0.012)
2.119μH coil: (L = 2.13μH)(R = 0.9Ω)(Q = 0.016)
1.025μH coil: (L = 0.79μH)(R = 0.05Ω)(Q = 0.06)
1.767μH coil: (L = 1.18μH)(R = 0.4Ω)(Q = 0.017)
I think most interesting was the 2.119μH coil, which was spot on. It was composed of 8 turns, 4 on top and 4 on the bottom, which all traveled clockwise. The board thickness was the standard 1.6mm FR-4.
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Love your work @Satur9
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Watching this thread with intrigue because I’d like to make a glove that powers my led. Lots to learn!
What board is in the back of the mockup xLED?
Great work being done here by all participants, I’m following Leeborg’s project with great enthusiasm 
For all the topics related to Leeborg’s project, you can check out this project thread:
There’s a sample circuit over there that you can build. We’re very close to passively lighting an xLED. More input would be appreciated.
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Oh, I’m already following the thread @Satur9 , and I do have a bunch of the 13.56mHz crystals waiting to be used, just waiting for the oscilloscope to arrive so I can make sure I’m on the right track