I stumbled across some unexpected data points when measuring the AC resistance of magnet wire. I varied the frequency of the AC voltage and measured the corresponding impedance of half a meter of 32 gage magnet wire. As expected, due to eddy currents the AC resistance of the wire is greater than the DC resistance for 1 kHZ - 10 MHz. However, the AC resistance of the wire drops below the DC resistance from 12 MHz to 20 MHz.
This is a hard trend to justify, since increasing the frequency of the voltage would increase the magnitudes of the eddy currents in the wire. Has anyone experienced a sudden drop in the resistance of a wire above a certain frequency?