[RFI] RF getting into 4-port wirelss router.

[Jim Brown]

I continue to refer folks to my extended (and rigorous) development of 
the fundamentals of this. A high Q resonance is effective ONLY at 
resonance, and it's a NARROW resonance, determined by length of the 
cable beihg choked. A LOW Q parallel resonance where the R at resonance 
his high is an effective choke over a wide range of frequencies, and is 
NOT sensitive to length of the line in the common mode circuit.

Those who are too lazy to follow and study the link deserve to remain 
ignorant, and will continue to believe that life is simpler than it 
really is.

73, Jim K9YC

On Tue,1/13/2015 9:46 PM, Roger (K8RI) wrote:
> On 1/13/2015 8:27 PM, KD7JYK DM09 wrote:
>> : That is NOT a choke, it is an inductor, which can resonate with a 
>> cable
>> : whose length makes it capacitive. An effective choke must cause the
>> : common mode circuit to have a high common mode Z at the frequency(ies)
>>
>> I guess there's no chance in Hell of it ever working then...
>
> Why?
>
> It is an inductor with substantial distributed capacitance forming a 
> parallel   resonant circuit with a very high impedance at resonance.  
> A very effective method of stopping RF passage. On a single line they 
> are often used with a series resonant circuit to ground to effectively 
> short out the remaining RF.