Thanks for the explanation! I haven't tried this yet but will do what the manuals for the old Gen Rad bridges suggest. They suggest "shunting down" the unknown and out of range impedance with a capacitance that will drop the impedance across the bridge to within the range of the bridge and then the mathematically remove the admittance of the known shunt capacitance to reveal the impedance that was out of range. I have done this with an old MFJ 259 (type that can measure Z's R and X but has a limit of about 1.6 k) to get an idea of the common mode impedance of a current balun......it worked well enough.
