In message , Owen Duffy
writes
"Geoffrey S. Mendelson" wrote in
:



1. Can I connect a 75ohm BNC plug (which is a different size) to a
50oHm BNC socket?

There is such a thing as a 75 ohm BNC connector, but you are almost
certainly looking at 50 ohm connectors designed for use on 75 ohm cable.
My recollection is that the 75 ohm connectors are incompatible with the
50 ohm connectors, and in some combinations will spread the female inner
part.

For all intents and purposes, 50 and 75 ohm BNCs (both male and female)
are interchangeable. They have essentially the same dimensions. You
might just see that the 50 ohm male has a rather stubby point, whereas
the 75 ohm version has a somewhat more steadily-tapered pin - but,
unlike N-connectors, the 50 ohm male certainly doesn't cause damage to a
75 ohm female.

The thing which mainly causes the impedances to differ is the amount of
PTFE dielectric present, in both sexes. On the 75 ohm version, you will
normally see that it has been reduced considerably compared with the 50
ohm. Even with less dielectric, the 75 ohm version is still a bit
unhappy with having too much, and this tends to lower the impedance to
somewhat less than 75 ohms.

However, for all intents and purposes, you probably won't notice any
significant difference between 50 and 75 ohm BNCs (mixed or not).
--
Ian