Re: Spaced Coil measurements.
I just ran your mutual inductance program to calculate the
inductance of the 10 turn coil. The answer is a lot closer but still
a bit too low (about 5%). Thanks for pointing out the correction.
> Withe the appropriate "current sheet" corrections for such coils the
> answers are wildly inaccurate. See any handbook such as the "Radiotron
> Designer's Handbook" for the correction terms. In my 1941 edition they
> are on page 142.
> By the way, Malcom, one of the QuickBasic inductance programs I sent
> you several years ago does include the current sheet corrections.
The really telling point about the measurements is that the wirelength
is starting to approach the 1/4 wavelength at resonance. If I kept on
reducing the turns, I'd eventually I'd end up with a piece of
straight wire which no-one could dispute was a poor resonator and a
good radiator at resonance. Also I was amazed at how well Medhurst
worked for this coil. While measurements of various kinds seem to be
reinforcing the lumped view of high Q open resonators, nothing of
real substance seems to have surfaced in countless measurements to
support the 1/4 wave view. I will pursue these msmts to the death and
send all details to the list when I get access to a suitable venue.