1-port impedance load is 50 Ohm's
Qfac is straight forward calculation of XL/R i.e. reactive component divided by resistive value.
SRF depends on fixture stray capacitance and Choke self capacitance.
At resonance, return loss has negative peak where maximum the Q= f/BW for BW = width of f band for delta 3dB of the resonance band from peak.
But this includes Q of parasitic C, so Q result of C must be much better than L to get good results.
1/Q=1/QL + 1/Qc. such that 1/Q becomes 1/QL.
Hi Q caps depend on f and desired Q , such as mica or plastic caps to measure Q of L at desired operating f.