[TowerTalk] Common-mode choke

[Jim Brown]

On 5/20/2014 9:31 AM, Jim Thomson wrote:
> are you sure 5k ohms is required ??

See the tutorial.  The higher choking Z provides better "worst case" 
noise suppression and greater power handling (because it reduces the 
worst case common mode current).

>   Steve is showing 1100 ohms resistive for the worse case
> scenario   where the coax is a half wave long.   1100 ohms  resistive would result in –30 db shield current.
>
> ##  W8JI designed all the dx engineering baluns..and they all use type 61....go figure.

I'm not designing " baluns," I'm designing common mode chokes. Tom's 
"baluns" aren't very good chokes -- I suspect that's why DXE also sells 
a "line isolator," which is probably a common mode choke. I haven't 
measured one.

73, Jim K9YC