Topband: Binocular Cores

[Tom W8JI]

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 at contesting.com>
To: "Topband" <topband at 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
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2014.0.4800 / Virus Database: 4311/9916 - Release Date: 06/01/15
>