[ARC5] Toroid for 9:1 Balun

[Roy Morgan]

On Sep 2, 2015, at 9:25 PM, Mark K3MSB <mark.k3msb at gmail.com> wrote:

> If I want a 9:1 impedance ratio, then my turns ratio needs to be 3:1.    I
> can do 3:1,   9:3,   30:10, etc.   I guess what ever values I pick should
> be spaced equally around the toroid?

See these web sites for further information about winding toroids:

http://kitsandparts.com/xtoroids.html
?is this the same outfit?  dunno:
http://partsandkits.com/toroids.php


From Micrometals, Inc, a manufacturer, 
-their home page with iron powder materials data and lots of other stuff:
http://www.micrometals.com/
-a technical treatise on losses:
http://www.micrometals.com/appnotes/appnotedownloads/chfsdltw.pdf
- at their application notes page, 
http://www.micrometals.com/appnotes_index.html
see especially these two:
1) Iron Powder Cores for High Q Inductors
2) Iron Powder Core Selection for RF Power Applications

The ARRL Handbook has quite a lot of information on toroids, their uses and characteristics.
My 1998 Handbook has a section “Component Data” with a subsection “Inductors and Core Materials”.  You’ll find much useful data there.  Note that powdered iron materials from Micrometals may be color coded, where ferrites are not.

The well known source: Amidon Associates:
http://www.amidoncorp.com/
-their specifications page is:
http://www.amidoncorp.com/specs/
- description of many of the standard materials:
http://www.amidoncorp.com/product_images/specifications/2-02.pdf
-and the specs for many common type materials are at:
http://www.amidoncorp.com/product_images/specifications/2-05.pdf



There are many calculators on the web that help you design toroid inductors - these can be used backwards to figure out what you might have in your hand.  
Use google with: "toroid calculator"
It is pretty hopeless to guess what is offered at a hamfest vendors table unless the type material is available.

Here is another handy tool for working with toroids:
http://www.electronicecircuits.com/electronic-software/mini-ring-core-calculator-pr

Roy 

Roy Morgan
k1lky68 at gmail.com
K1LKY Since 1958