On 3/20/17 4:34 AM, Máximo EA1DDO_HK1H wrote:
Guy, my question is NOT about common mode current.
Is NOT about how much impedance a choke provide.
My only question is to know if (and how) a "common mode choke" is able to balance
different "differential currents".
Do you remember the famous I1, I2 and I3? Where I3 is the common mode current
the choke suppress.
So ,my question is about I1 and I2.
If I1 and I2 are different values at feed point, Is a choke balancing them?
Make them equal values into the coax (not antenna side, only coax side) ?
Or a choke has no effect in I1 and I2 differential mode currents?
Yes it does force them the be equal..
Think of the two wires as a and b, so the current in one wire is Ia and
the current in the other wire is Ib.
Ia = -Ib (because there's no where else for the current to go)..
Say that a is connected to the center pin, which is I1, and b is
connected to the outer shield, the currents are I2 (inside the coax) and
I3 (outside the coax)
So Ib = I2+I3
if we force I3 to zero (by putting a big impedance in that leg)
then Ib=I2
so I1=-I2, which is what you want.
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