[Boatanchors] Toroids

[Carl]

I use a handheld LCR meter and wind 10T of  wire on the core. Then use 
the standard formulas to determine Al value. Then try to find one of the 
common manufacturers offerings that are a close match.

Most of these larger unknowns that Ive found are OK for RFI chokes and 
LF-MF baluns but not much use on HF and up. With the paint its pretty 
hard to tell if the core is ferrite or powdered iron so some method of 
testing is required. Micrometals has an established color code and 
others seem to have no problem using some of those colors on an entirely 
different mix.

Carl
KM1H


----- Original Message ----- 
From: <Telegrapher at att.net>
To: <Boatanchors at mailman.qth.net>
Sent: Thursday, March 26, 2009 2:39 PM
Subject: [Boatanchors] Toroids


> Is there any way to determine characteristics of toroids?
>
> I've got some here, large types, that only have a number like 
> A-759135-2, Turquoise in color, B-957020-3 which is kind of an 
> orangish-brown and D-093075-3 which is brown.  Different dimensions 
> and i don't know whence they came from.  Heavy little donuts to say 
> the least.
>
> larry
> W0OGH
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