Subject: Re: How to check for a 50 or 75 ohm connector
Summary: What do you think of these ping times eh?
Reply-To: You can't see me, and I pass right through planets...
References: <3E053579.AFE0BFDF@sympatico.ca> <3keudKjAZXB+Ewcs@newbrain.demon.co.uk> <email@example.com> <1fzeD1n3UdB+Ewe7@newbrain.demon.co.uk>
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Date: Sun, 22 Dec 2002 20:28:54 GMT
NNTP-Posting-Date: Sun, 22 Dec 2002 15:28:54 EST
On Sun, 22 Dec 2002 18:45:21 -0000, "Brian Reay"
> "DarkMatter" wrote in message
>> On Sun, 22 Dec 2002 15:07:35 +0000, Ian Walker Gave
>> This is because a BNC connector has a physical spec on the mating
>> side that is impedance independent.
>How is this achieved? The mating part is coaxial so how is it made
The ground shroud that encircles the center pin is always the same
distance from said pin, and said pin is the same size, and the twist
barrel is the same. Otherwise, one could not plug a BNC connector
into a BNC jack. Now, the insulation of each may or will differ as
the dimensions of those items differ due to cable differences. That
>You can see the mismatch if you have a 75 ohm connector in a 50 ohm system
>with a good network analyser-- even if the cable is correct.
If some dip places one size cable into the rear of a BNC connector
made to accept another size cable, it will be wrong. If it matched to
the cable, it will be the right connector. The BNC PLUG/JACK side is
the same though.
>As regards the original question, I'd suspect the bag to be full of 50 ohm
>parts as many are coming onto the surplus market as LANs are changed to Cat5
>(or 6) from the old coax based systems.
Coax hasn't been used in ethernet networks since the 2 Mb/s days, or
obscure topologies like TCNS.
10baseT has been around a long time. Where have you been?
Connector surpluses? Hahahaha... That's funny.