On Sun, 26 Sep 2004 19:38:02 -0500, "John Smith"
wrote:
Please give me more information about the ferrites...

Hi John,

Visit:
http://bytemark.com/products/content2.htm
You will find background information here, but unfortunately they
don't maintain the pages very well and some information is lacking.

How many do I need?

Depends on application. You want at least 3 times the expected load
Z. Ferrite Z is bulk determined and the usual standard of bulk size
is defined as a type 101 size bead.

What permeability?

Type 43 or 64 material. 64 being slightly better (by about 15%).

Who makes them capable of 450 MHz or so?

Amidon, but this is not proprietary (although the type specification
may be). There are other manufacturers like Fairite.

73's
Richard Clark, KB7QHC