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Re: [TowerTalk] Cores

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Cores
From: jimlux <jimlux@earthlink.net>
Date: Sat, 9 Apr 2016 10:41:47 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
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.



Sent via the Samsung Galaxy S®6 active, an AT&T 4G LTE smartphone
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