I'm wondering if there is a way to measure impedance, from end to end on a long lead (75 cm with a coiled inductor), without picking up the antenna effect of putting into a circle. Are there long impedance probes that can be calibrated?
You have two wires. The exact disposition of these wires will effect the measurement. Therefore you have to leave these wires in their final configuration for how they will be used. You then set up test leads to where the connections are required. You then use a link wire between the test leads to do your "zero" calibration. The extra you get when using your real circuit tells you what you need to know. You then need to add in the inductance of the straight link wire which you calculate from standard formulae.