[TowerTalk] Cores

[jimlux]

On 4/9/16 9:53 AM, Arnie Pfingst wrote:
> I frequently read about different mixture of ferrite used to make cores used for different frequency. Over the years I managed to accumulate a box of different cores. There are lots of different colors, from light yellow you purple, sizes ranging from 3\8 to 4 inch, and shapes from simple round to square and lots in between. How can I tell them apart. Arnie Kd6cz
>
Do you have some sort of antenna analyzer or way to measure impedance?

You wind a turn or two of wire through it and measure the inductance.
That will give you the AL value, and from there, looking up the size of 
the core and trying to find a matching value.

This isn't perfect, but it lets you rapidly sort through.

If you can make the measurement at an appropriate RF frequency, then you 
can figure it out by looking at the R and X, and, again, matching it to 
a mfr data sheet values.

Not all companies use the same color codes, of course.

But, you can do something like gather all the yellow ones together, and 
if there's two different mixes in the yellows, the impedance test will 
usually separate them.



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