[TowerTalk] Balun for Force 12 6 Element 20 Meter Monobander

[Jim Brown]

On 7/21/2020 10:38 AM, Steve Maki wrote:
>  From what I've heard, the properties of ferrites can vary wildly, 
> especially from run to run, so unless you measure the one you make, you 
> don't know.
> 
> OTOH, I'm not sure that it's possible to make a choke using recommended 
> (by K9YC) method & parts and end up with a *useless* choke.

My recent (2018) Cookbook is the result of measuring several hundred #31 
cores, selecting four at opposing limits of their characteristics, 
winding chokes on each, and tabulating Z data in a spreadsheet for each 
ham band. Recommendations for each band and each cable type are on the 
basis of the choke meeting spec on the WORST of those cores as well as 
the best.

73, Jim K9YC