You really need to do a single loop through the core windows and measure the
impedance with some sort of analyzer. Even an MFJ259B with a short
connection to the jack will work well for this.
If the resistance equals the reactance down somewhere around 2 MHz, it is 73
material.
If R=X someplace much higher, you can be sure it is a different mix. The Q=1
frequency, where R=X or where loss tangent crosses reactance, tells you the
material better than anything else you can do.
That is how I quickly sort unknown cores.
73 Tom
----- Original Message -----
From: "Roger Parsons via Topband" <topband@contesting.com>
To: "Topband" <topband@contesting.com>
Sent: Monday, June 01, 2015 10:13 AM
Subject: Topband: Binocular Cores
I have some binocular cores which I know are FairRite mix 73. I have others
which I thought were also mix 73. However, the first ones measure about 50k
Ohms with ohmeter prods onto their surface, whereas the others only measure
about 1k Ohm. I don't believe that that is a defined parameter, and am
aware that the test is not very scientific, but I am surprised to see such
a difference. Thoughts?
73 RogerVE3ZI
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