[TowerTalk] Test Fixture for Common Mode Chokes

[Brian Beezley]

AC0C said:

"Brian, would you consider the N2PK VNA in the "fancy" category rearding 
your calibration comment?"

Jeff, I don't think the N2PK measures all four S-Parameters nor does it 
do a 12-term calibration. I was thinking of the HP 8753C and 8753D, 
which are sophisticated VNAs that a surprising number of hams have.

I confused some things in my last message. The NanoVNA compensates for 
the port 1 impedance when doing a single-port calibration, but I don't 
believe the stock firmware compensates for it when doing a two-port 
calibration. Also it is the port 1 impedance that was so far off for the 
particular NanoVNA-H4 N6LF tested, not port 2.

I'd be interested in seeing an .s2p file for the commercial test 
fixture. If the S21 method is good enough without going to the trouble 
of making a Y21 measurement, that would be good to know.

Brian