[time-nuts] 75Z vs 50Z for GPS receivers (was Re: ACE-III GPS receivers (Dr Bruce Griffiths))
John Ackermann N8UR
jra at febo.com
Sun Jan 28 08:22:47 EST 2007
Christopher Hoover said the following on 01/28/2007 04:48 AM:
> I would also add that BNC and N connectors come in both 50Z and 75Z flavors.
> In fact 75Z BNC connectors are pretty common, being used in professional
> video applications. (Check surplus BNC patch cords carefully.) On the
> other hand, 75Z N connectors are much less common, but were used in CATV
> plants, IIRC.
Just as a further note, 50 and 75 ohm BNCs will interconnect (the metal
parts are the same, with the impedance difference coming from the
dielectric used) but 50 and 75 ohm N connectors don't -- the center pin
of the 50 ohm version is thicker. If you mate a 50 ohm male with a 75
ohm female, you will damage the female. If you mate a 75 ohm male with
a 50 ohm female, the connection will range from shaky to nonexistent
depending on how well centered the pin is.
John
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