[TowerTalk] K9YC Choke Cookbook Question

[Jim Brown]

On Sat,2/4/2017 12:55 PM, KD0Q-Glenn wrote:
> Several places in K9YC's material indicates that bifilar chokes wound 
> with close spaced enameled wire would have an impedance of 
> approximately 50 ohms and those wound with close spaced THHN would be 
> 80-90 ohms.

This is correct.

BTW -- I first noted the Zo of these two chokes in a later version of 
Jerry Sevick's (W2FMI) book.  Quite a few years later, I built and 
measured similar chokes and confirmed his results to reasonable 
measurement accuracy.

73, Jim K9YC

>
> In Chapter 7 of K9YC's  "A Ham's Guide to RFI, Ferrites, Baluns, and 
> Audio Interfacing" the table for bifilar chokes shows the THHN wound 
> chokes at 50 ohms and 2/3 of those wound with enameled wire at 85 ohms.

This is a typo.  Thanks for pointing that out!