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Weird Test

I tested a short run with my Fluke 2000, and it gave me an error I'd never seen before. I got the excessive delay skew, 95 where the max is

50nS. Usually the cables have only a few nS, less than 5 between pairs. Anyway, I cut it off and repunched it down and the problemn went away.

When I think about it, having 95nS delay skew between pairs means that at about a foot per nS, there's 95 extra feet on that pair! And we all know that can't be. :-/

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You'll be glad you did! Just when you thought you had all this figured out, the gov't changed it:
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Reply to
Watson A.Name - "Watt Sun, th
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Maybe there was a distortion in the space-time continuum in that particular section of cable ;)

Reply to
Goonerak

I can 't remember if it was 45 feet or 54 feet long. Methinks it was just Fluke. :-P

Reply to
Watson A.Name - "Watt Sun, th

Consider it a fluke ;-) delay skew is definitely a cable-only related parameter, so you are correct: re-punching would not have fixed the problem. IF there was a problem indeed.

When technology-related explanations are exhausted, it is usually wise to look into human-induced possibilities. Like, someone's playing a practical joke or some error in operating the machine

Reply to
Dmitri(Cabling-Design.com

On a second thought though:

The way Fluke cable testers work (they don't call it DSP for nothing) is: the tool sends a short pulse into the cable and, by doing the Digital Signal Processing magic, devise all the parameters from the way the pulse is distorted when it hits the other end. You've mentioned it was a short cable. It must have been the case when the signal is so strong that it travels the same piece of cable twice, and some echo showed up exactly 95 ns after the first signal, which means that it is actually 95ns/3 (traveling DSP-remote-DSP-remote instead of just DSP-remote), which is conveniently within the spec.

Just my 2c.

Reply to
Dmitri(Cabling-Design.com

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