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Old 9th Oct 2018, 6:36 pm   #20
Al (astral highway)
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Join Date: Nov 2006
Location: London, UK.
Posts: 3,496
Default Re: Determining Zo for coax cable

Quote:
Originally Posted by Skywave View Post
If you have test equipment for measuring inductance and capacitance and you need to know the characteristic impedance of a length of coax ...
Hey Al,

I'm scratching my head here.

If the characteristic impedance of some coax is 75 Ohms, (or 50ohms, for that matter), why should I need to measure it?

I don't understand the rationale.

I know from many of your posts that you like to know exactly what you have to hand and often do theoretical calculations, but in this case, I'm left wondering why you wouldn't trust the manufacturer's spec?

I do know how characteristic impedance is theoretically determined and I also note David's reassuring comment on tolerance in post no 2. of the thread.
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