I have spent hundreds, maybe a thousand or more hours, at the bench with just (LI-ION) 18650's; the cells themselves, and every variation of their management IC's around. I now build my own management boards for projects from 3Wh's up to 10kWhs. I have a 23 page index of cells, from various manufactures, even current down to contact names and numbers.
I do not know much about Spectrum Analyzers but I have 18650's pretty well covered. I still have about 4000 of them here that need a good home (all tested) and another (approx) 10k sitting in original packaging (from laptop packs, cordless drills, cordless vacuums, flashlights, LED drivers, hoover boards, e-cig, and several other...)
I am just griping...I guess it makes me feel left out that noone asks for me help with matters concerning 18650 builds...getting old and fussy.