I'm pretty sure the "red" cores are type 2 powdered iron cores having a
permeability of 10. Actually the cores are usually red on all sides but
one which is brown.
Jim Brown wrote:
> On Sat, 28 Mar 2009 17:00:41 -0700, Dan Sawyer wrote:
>> 43 cores are used in rf power transformers for similar frequency
> I don't know what a "red core" is, but I know a lot about the Fair-Rite
> #43 material. It has low loss at low frequencies, and high loss at high
> frequencies. I would NOT use it where the core needed to carry much
> power above a few MHz. How much is "much?" A 2.4-inch #43 is going to
> get hot with 100 watts at 14 MHz, and hotter at 28 MHz. Fair-Rite #61 is
> a good material for HF transformers in the 100 watt range.
> It is quite useful to study the material electrical properties in the
> Fair-Rite catalog that is on their website.
> Jim Brown K9YC
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