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Old June 4th 07, 04:01 AM posted to rec.radio.amateur.antenna
Roy Lewallen Roy Lewallen is offline
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First recorded activity by RadioBanter: Jun 2006
Posts: 1,374
Default Trying to find out what Ferrite material this is.

Larry Benko wrote:

Look at the L/C meter from AADE (Almost All Digital Electronics)
www.aade.com which a 1 hour kit for $99. It is quite accurate and uses
a variable frequency oscillator so that smaller values of inductance and
capacitance are measures at higher frequencies. I own an 8753 HP
Network Analyzer and still use the L/C meter most of the time since it
is so convenient. It easily can tell the differences between
73/43/31/61 materials. I usually wrap 2 turns thru the torroid to do the
measurement.

73,
Larry, W0QE


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