Topband: Core for K9AY loop transformer

[Jim Brown]

On Sun, 25 Mar 2007 15:46:15 -0230, RFD wrote:

>In looking on the FAIR RITE web page I see that type 43 material is
>spec'd for freq range 25-300 Mhz.  So why use a material for that
>range...what gives?..

When you use a ferrite to wind a transformer, you want LOW loss. 
When you use a ferrite for suppression of RFI, you want HIGH loss. 
The Fair-Rite catalog is listing this as a suppression part, and 25-
300 MHz is the range where it has relatively high loss. It is a low 
loss part below 10 MHz, and thus a fairly good choice for winding 
Beverage transformers. 

There's a lot more about ferrites in the tutorial below.

http://audiosystemsgroup.com/RFI-Ham.pdf

73,

Jim Brown K9YC