IF transformer VNA Characterisation

When I lived in Germany, I joined DARC (as you do) and showed my new
sausage-noshing friends some examples of my construction handiwork. As
a result of that, they gave it a specific German portmanteau term  to
describe it: Scheissebau. I haven't looked up the translation but I'm
guessing it means 'ingeniously-resourceful.' ;-)
Anyway, here's a prime example. I have several hundred broadcast radio
intermediate frequency transformers manufactured in the early 1970s.

https://disk.yandex.com/i/Ym1YrWS2YGTnxw

I was curious as to what IF they were made for. Each of them is
color-coded to indicate this, but I have no chart to de-code this and
online sources conflict in many respects. The obvious answer was to
test them all and create a chart from those findings. This
necessitated the building of a test fixture to accommodate the
transformers, which can be plugged into it and swapped around for
purposes of comparison. Having built this, I then needed to make up a
calibration kit to establish a reference plane to subtract the effects
of the hook-up cabling and connections. Fortunately, de-embedding and
whatnot is no big deal as these IFs are low, so the parasitics (which
I'm not proud of) in this construction shouldn't materially affect the
measurements.

Here's the fixture:
https://disk.yandex.com/i/NE8B4i5Yh0jWYA

A specimen IF for testing:
https://disk.yandex.com/i/BUpamDpN8us8pQ

The ad-hoc calibration kit:
https://disk.yandex.com/i/CaV7QGfA-KtP_w