Inputs/outputs on old Bell tube amplifier

[ESigma25]

I've acquired an old Bell tube amplifier (model 3715-B) from the mid 1950s and it's got some rather...interesting input and output connections.

The inputs use some kind of modified UHF connector with no center pin hole:

https://i.imgur.com/8aegH4x.jpg

And the outputs use something that looks like a UX4 tube socket:

https://i.imgur.com/Rgp9s7B.jpg

Can anyone help me identify these connections so I can try and adapt them to something more standard?