hello ed
I wish I had a TDR !!
I put some photos with a test (@ 800 mhz +0 dBm) just for fun
the strange thing is that even if I invert the two bnc of the coupler the tracks do not move (always first the white track and then the green)
I didn't understand this thing .......

https://groups.io/g/TekScopes/album?id=256551