Since posting earlier I've been on to the actual manufacturers and they
reckon these plugs are actually 50 ohms. So the supplier's insist
they're 75 and the makers say they're 50! I need to know for sure, as
one or the other is in error. How can one tell, by visual inspection
and or physical measurement, which type is which? There must be
something that's visibly different about the two types.
THanks.