[RFI] Fwd: BIFILAR COMMON MODE CHOKES

[Jim Brown]

On 8/20/2023 4:27 PM, David Eckhardt wrote:
> I do not use coax on the HF set of wires.  I use parallel conductor 
> transmission line.  No more than 8-feet of coax in my HF setup.  So I 
> need to both reduce common mode currents and transition from CM to DM.  
> These CMCs accomplish both in my application.

There's nothing magic about parallel wire line that provides balance. if 
It's what's at the termination that provides balance (or imbalance). And 
the common mode current is on both conductors, a value equal to the 
difference in the currents in the two conductors at each point. In other 
words, it's STILL part of the antenna, and chokes work exactly the same 
way, whether wound with coax or parallel wire line. My designs use both 
interchangeably, the practical differences being Zo in the range of 100 
ohms for the two-wire chokes.

Yes, the chokes will work if well designed. But your CMMR measurements 
into 50 ohms tell us nothing about that. It's still the antenna model.

73, Jim K9YC