The little Sony monitor/TV from that reeel to reel
setup also had a full
size "UHF coax" connector. I used that for the video for my first TRS80.
Yes, that conenctor (We generally call them PL259s and SO239s (plug and
socket respectively) over here) was quite common on video equipment at
one time. I have no idea why, it's not even close to constant impedance,
and it's very easy to make a right mess of soldering the plug to the
cable. The BNC connecotr is a lot nicer.
There was a popular monochrome monitor over here in the late 1970s/early
1980s. I think it was a Nitachi, the case was grey-painted metal with a
black plastic front panel, it was almost cubical in shape, and came in 9"
and 12" versions. I came across them used with Apple ][s, RML380Zs, etc.
Anyway, that used SO239s as the input connectors.
-tony