Reply to thread

As far as I've understood the question is what's the impedance seen by the filter; so we are interested to S22 (right side) and not to S11 (left side). If the the cable is terminated onto Zo, then S11 will be Zo. But we are interested in S22 where the termination on the other side of the cable is 10k. This means the load doesn't match the impedance of the cable, this means the impedance seen by the filter will not be 10k.

Possibly I was not been clear enough in my previous posts.