John Popelish wrote:
I would have to graph this on a log frequency plot to see the frequency
breakpoints, but I think this looks a lot like a short piece of
transmission line below about 6 MHz and like a resonator above that. I
expect the delay to start to fall at higher frequencies as the
turn-to-turn capacitance takes over.

What do you see?

I see something that resembles part of a sine wave with
a point of inflection (resembling a zero crossing) around
10 MHz. The phase shift around 10 MHz is 60 degrees per
MHz. The phase shift above and below 10 Mhz is lower.
I sure can see why the lumped circuit model is a total
and complete failure when applied at 10 MHz. I also can
see why Dr. Corum chose 15 degrees as his cutoff point.
--
73, Cecil http://www.qsl.net/w5dxp