[TowerTalk] RG-8X Crimp BNC Connectors

[Paul Christensen]

>The impedance determining portions of the BNC connector are
>exactly the same as those of the N type connector.

Agreed.  The proportions to the equation that determine characteristic
impedance are the same for any 50-ohm connector.  My specific wording  was
that I don't consider the BNC to be a "true" constant impedance connector
because of the swept impedance bumps I've seen on instrumentation test
cables at frequencies above 500 MHz.  The "N," "TNC," and "SMA/SMB" types
exhibit superior "constant" characteristics when swept at the higher
frequencies, particulary properly crimped "N"  and sexless GR types.

>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.


Agreed again.  However, I am sure that the PL-259 can be calculated to
*some* characteristic impedance using the formula to derive the
characteristic impedance of coaxial cable.  Although, the PL-259 has been
connotated as a "UHF" connector, sweeping it to the upper UHF frequencies
reveals that (arguably) it should not be used in critical applications above
100 MHz or so.

-Paul, W9AC


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