[time-nuts] BNC question

[Bruce Griffiths]

Chuck Harris wrote:
> Greg Broburg wrote:
>
>>> receivers used 75 ohmantenna
>>> <http://en.wikipedia.org/wiki/Antenna_%28radio%29>inputs, so they
>>> often used 75 ohm BNC connectors.
>>>
>>
>> I had remembered that it was a 75 ohm that would damage a
>> 50 ohm socket. This article states that a 50 ohm would
>> damage a 75 ohm socket.
>>
>> Greg
>
> Sadly, you remembered incorrectly.  Both 75 ohm, and 50 ohm
> BNC parts use the same center pin assemblies.  The only
> difference is the 75 ohm part has the teflon shroud removed
> from around the female pin.  They mate in all combinations
> without any risk of damage.
Not necessarily true, BNCs intended for use with RG59 cable with either 
a 0.7mm diameter pin or a 0.9mm diameter pin are readily available.
Whilst one of these may now be non standard they are nevertheless they 
are still available from Chinese manufacturers at least.

>
> The N style connector is a different story, however.  It is
> a higher performance connector, and as a result they needed
> to make the center conductor of a 75 ohm connector smaller
> in diameter all the way through, so the 75 ohm center male
> pin is slender, as is the 75 ohm center female pin.  If you
> jam a thicker 50 ohm center pin into the slender 75 ohm
> female pin, it will bend the socket leafs out and probably
> break it.
>
> -Chuck Harris
>
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