Hi Gaius,
Gaius Inscribed thus:
In article ,
says...
A 75 ohm BNC plug is identical to a 50 ohm
one, save that the male pin in a 75 ohm plug is smaller in diameter.
The other way round, a 50 ohm BNC plug will damage a 75 ohm BNC
socket.
Thats what I said... :-(
Sorry. Not so. This is one of the most common urban myths in RF
engineering. The pin diameters of BNCs are identical between 50 and
75R. (Measure them !!)
I did... :-(
The 50R and 75R connectors are mechanically compatible in BOTH
directions. Don't take my word for it - check Amphenol's
specifications: "Two distinct types of 75ohm BNCs are available, and
both mate with each other and with 50ohm BNCs. "
I did check that documentation... :-(
I've been using 75R and 50R interchangeably for about thirty years,
and I've had NO mating damage problems. (Mismatches don't worry me -
HF only).
I've probably used them for nearer 50 years, and had to replace damaged
sockets because the bifurcated female pin had one side broken off. I
am aware that some of the early plugs didn't have solidly captive pins
and could move forward and cause damage. Greenpar package the
plugs/sockets clearly marked 50 or 75 ohm. In all that time I've never
bothered to check the specifications until now.
Note - type N and type C connectors WILL be damaged if you try to mix
75R and 50R varieties. I suspect this is the source of the BNC myth.
Having taken your words and accept that I'm wrong, I can only agree that
you're right and it is a myth.
Thanks for the insight.
Also - some Chinese made BNCs are so badly made that they will damage
other connectors - but this is a manufacturing tolerance issue.
73's
--
Best Regards:
Baron.