>From: "Paul Christensen" <paulc@mediaone.net>
To: <towertalk@contesting.com>
>Date: Mon, 21 Sep 1998 17:25:33 -0400
>
>I have never considered a BNC connector to be a truly
>constant-impedance connector.
The impedance determining portions of the BNC connector are
exactly the same as those of the N type connector. So to
whatever extent the "N" connector is a controlled impedance
connector so is the BNC.
In fact, I have heard somewhere that BNC stands for "Bayonet N
Connector". The BNC and TNC are non-weather sealed versions of
the basic type N (I think this originally referred to "Navy")
controlled impedance guts. Either the BNC or TNC female can in
fact (but shouldn't be) mated to an N male (of similar intended
impedance) and function correctly for RF purposes.
>Constant impedance applications require the use of
>constant-impedance hardline, "N," "TNC," or the "SMA/SMB,"
>et.al., variety of connectors. I also disagree with your
>assertion that a "UHF" PL-259 connector is both a 50-ohm and
>75-ohm connector in one!
This is probably correct. I also doubt that it is either a 50 or
a 75 ohm connector. But the point is simply that it is NOT a
controlled impedance connector (for any particular impedance) and
as such is equally applicable to either impedance line. Note
that they don't make different versions of this connector for
different impedances as they do for the controlled impedance
types.
73, Eric N7CL
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