Roy Lewallen wrote:

That looks like a handy gadget. It wouldn't be very good for working
with the kinds of ferrites often used for baluns, wideband transformers,
or EMI suppression because of the very low Q encountered. Many of the
ferrites I use have a Q of one or less over at least part of the
frequency range of operation. And of course the L/C meter wouldn't be
useful in assessing the loss or Q of inductors at all. One of the unique
things about the HP unit is that it's able to resolve very small R in
the presence of large X or vice-versa, which is very difficult to do.
But then it costs a couple of orders of magnitude more.

A network analyzer is poorly suited for making measurements of
impedances which are a great deal higher or lower than 50 ohms.

The problem with any of these instruments is that they'll all happily
give you an answer, often to several decimal digits. But as Owen pointed
out for the 259B, the answer can be anywhere from good to total garbage.
The only way to know which is to understand the limitations of your test
equipment and something about the nature of the component you're trying
to measure. There just isn't any instrument which will do the thinking
for you.

Roy Lewallen, W7EL

That is what I thought also Roy but the little L/C meter seems to work
pretty well with low Q inductors. It is not measuring impedance but
measuring a frequency of an inductor and known capacitor in an
oscillator. The Q does change the oscillating frequency but not that
much. As I said before it is super easy to tell the difference between
77/31/43/61 type ferrites. Of course the permeability difference
between those types is a factor of 2 or more so ultra accuracy is not
important. The original question was how to determine what type an
unknown core was and not what impedance it represented at a certain
frequency.

I just grabbed 3 FairRite 59XX003801 torroids (2.4" OD x 1.4" ID x .5")
in 3 materials and measured a single turn with the L/C meter.

Material 61 (u=125) calc. inductance = .173uH, measured = .177uH
Material 43 (u=800) calc. inductance = 1.07uH, measured = .930uH
Material 75 (u=5000) calc. inductance = 6.85uH, measured = 7.39uH

The calculated inductances came from the FairRite catalog. I would say
the "low Q" inductors measured pretty well and the materilas were very
easy to distinguish.

73,
Larry, W0QE