BNC Connectors compatibility

[001]

Hi!

I`gonna make few BNC RG58 paches for my gear (FG, Scope etc. all my works BELOW 100Mhz)

BUT I see around only two types of ruged BNC connectors
One is 75Ohm Neutric (well, it is truly 75Ohm and needs RG59 but build WERY well since it is Neutric)
And  other sturdy variant is some china "soldering+nut" type wich is fitted to RG58 but center pin looks so thin like common video 75Ohm BNCs

What the way?


I`m google for it and many peoples says what diameter of center pin is a horrible problem.

[dmills]

If the connectors are correct then for BNC the pin geometry is the same between 50 and 75 ohm parts, but the insulating sleeve extends further in one variant.

Thus 50 ohm and 75 ohm BNC parts should mate without damage (This is **NOT** true for N type connectors!).

There have however been some BNCs made that did not meet normal specifications, I forget who the guilty party was, but someone stuffed this up, so there were some 75 ohm parts around that did not behave well with 50 ohm mates. 

I am surprised by you having trouble finding proper 50 ohm parts, Telegartner/Huber-Schurner/MA-Com/Amphenol should all have the good stuff I would expect.

@100MHz it probably does not much matter, unless you are trying to make metrology grade measurements, so use whatever comes to hand.

Regards, Dan.

[001]

I am surprised by you having trouble finding proper 50 ohm parts, Telegartner/Huber-Schurner/MA-Com/Amphenol should all have the good stuff I would expect.

I`m far from "golden billion" lands and simply cabbage parts what I see
Sanx for quick answer

[David Hess]

I have found that using double shielded cable makes for a much more reliable interface between the connector and cable.

[fcb]

Try to use the correct impedance BNC for your application (scope's, RF are 50ohm, video is 75 ohm).  Whilst damage from the wrong impedance BNC is unlikely, I've certainly had problems with different BNC's centre pins spoiling sockets - tends to be more brand specific though and I can't remember the details (back in the 90's).

[dmills]

There was someone doing horribly broken '75' ohm BNCs back then, I cannot remember who it was, but a load of the evil things got into the TV production game and caused all sorts of pain.

There is something to be said for NOT buying the cheapest connectors you can find, unreliable test leads are annoying (But you have not discovered the horror of expensive RF leads until you acquire a network analyser).

Regards, Dan.