[Mr.T]

"Geoff" wrote in message
...
I found many of those connectors went black and gave very poor
connections decades ago.
I'd be surprised if any are still in service myself.

The black was probably on a silver contact, and is actually and excellent
conductor !

I was expecting someone to suggest that, although I imagine it was caused by
other impurities entirely. Unlike much more expensive RF connectors, silver
content was probably not significant, if any, and the connectors did give
poor contact unfortunately. A regular clean or rotation was necessary IME.

MrT.