Please post the results. Once I get my 2nd pair I should be able to do the same with my 8753B. Meanwhile I'll sweep the current pair back to back on my 8560A.
I finally got around to playing a little.
Calibrated the 8753C for S11 with an old 85032B N calibration kit using an existing APC7-NM adapter on Port 1.
I put the two APC7-NF adapters from the 85032B back to back and added a 909F load. This is the lower trace below, then did the same with the Chinese adapters. The resulting upper trace speaks for itself:
To prove to myself nothing horrible was going on, I removed the adapters and attached the calibration load - (909F.gif). The lower trace is now the calibration load. It looks reasonable and is about what I'd expect measuring the load I'd used for calibration:
So I then tried one Chinese adapter with a 909C APC7 load - (SingleAPC7-909C.gif):
And finally, a 909C N-F load (909C-N-F.gif) - to see what we can expect out of a 909C compared to a 909F. The 909C isn't as good as a 909F. It's the flatter of the two traces. (Unfortunately, the plot capture didn't draw the traces in different colors.)
I didn't do any S12 measurements... I have two semi-reasonable Mini Circuits N-M to N-M cables. One is intermittently bad. I could only find one at work today and I think it's the bad one. Let me know if there are any particular measurements you'd like.
Edit: Embedded the images and added final comment.