[RFI] Yet another balun question

[Jim Brown]

I just downloaded and skimmed Andrew's QEX paper from docfoc.com (google 
found it).

Several things jump out at me. First, there is NO attention paid to the 
ferrite material -- it appears to be assumed as ideal, with no loss.  
Second, the fundamental property that makes a ferrite common mode choke 
work is the LOSS coupled from the core and its resonance. This is also 
ignored. Third, the core used in his experimental work was a Fair-Rite 
#61 material. This is is rather high-Q material, so its resonance is 
both narrow and difficult to measure. It is a VERY poor material for a 
common mode choke in the HF range, for reasons noted in my tutorial.

Bottom line -- the analysis is far to simple, and thus is flawed.

73, Jim K9YC

On Wed,6/29/2016 9:09 AM, JW via RFI wrote:
> re: ZS1AN's cascade
> Are we talking ferrite loaded TLTs (transmission line transformer) or flux coupled transformers and ferrite loaded "chokes" in his design?
> I can never keep this current-voltage balun stuff straight.
> de Jim WB5WPA