[time-nuts] BNC question

[Stan, W1LE]

Hello Joe,

It probably is a 50 ohm BNC female connector.

Check out a male loose connector with a known 50 ohm center pin.
Does the male pin fit the female nicely ?

I have rarely seen a 75 ohm BNC center pin, but they are out there.
I have never seen a 93 ohm BNC center pin. (never looked for them.)

If you apply a true 75 ohm BNC male connector to a 50 ohm BNC female it 
may not mate properly with a
low resistance joint.   ie. poor mechanical fit.

If you apply a 50 ohm male BNC into a 75 ohm BNC female, you will 
probably destroy the female center pin.

Cost wise, the 50 ohm BNC connectors are the least expensive, so that is 
what manufacturers use.
For most applications the electrical length of the center pin is a very 
small part of a wavelength,
so there is only a very small impact on the impedance, on the rare 
occasion impedance is of concern.

Stan, W1LE






On 4/9/2011 6:53 PM, Joseph Gray wrote:
> I have an old Arcnet hub that I want to salvage the isolated BNC
> connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
> and 75 Ohm versions of BNC connectors, but the ones from the hub look
> like a 50 Ohm BNC to me.
>
> I want to use these isolated BNC connectors for a frequency
> distribution amp. What do you think?
>
> I'm still trying to find some old Ethernet cards for the transformers.
> I know the cards will have BNC connectors, but the hub has eight
> matched BNC connectors, so using them would be preferrable.
>
> Joe Gray
> W5JG
>
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