RadioBanter - View Single Post

December 3rd 05, 09:48 AM posted to rec.radio.amateur.homebrew

wrote:
From: Roy Lewallen on Fri, Dec 2 2005 4:20 pm

wrote:

Since Bill Amidon sold his business to another company, the "new"
Amidon company has been reselling another company's toroidal core
forms.
. . .

I didn't know that anyone else but Micrometals made powdered iron cores
suitable for RF.

I have a few left-over Arnold Magnetics powdered-iron toroidal
cores that were used by RCA Corporation back in the 70s. For
the high end of HF for maximum Q.
. . .

A look at Arnold Magnetics' current catalog doesn't show anything
suitable for HF or above(*). Do you know of any company other than
Micrometals that currently sells powdered iron cores suitable for HF?
I'd guess that while low frequency powdered irons are still pretty
widely used in power supplies, the market for RF powdered iron cores
must be relatively small.

(*) That is, materials having low loss at HF and therefore suitable for
use as cores for inductors in tuned or relatively high-Q circuits. Like
ferrites, powdered irons having high loss at HF can be very useful as
broadband transformer cores, chokes, and in EMI suppression.

Roy Lewallen, W7EL