I have an inductor which has three coils, L1, L2, L3. In normal use L2 and L3 are connected in series, and resonated with a capacitor. L1 would then drive the tank circuit.
In Spice, I need the coupling factor "K" which is found by measuring L1 with a second winding open and shorted, K=sqrt(1-(L2s/L2o))
Is it more accurate to take the K measurement for each winding independently against the others, or should I just series connect L2 and L3 and measure a single K for L1 vs the series combination of L2 and L3?