Kitz Forum
Broadband Related => ADSL Issues => Topic started by: Weaver on October 24, 2020, 11:53:06 PM
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Regarding the ill that is documented at https://forum.kitz.co.uk/index.php/topic,24614.0.html, could anyone suggest an electrical engineering diagnosis for the kind of thing that can cause that frequency response ?
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It seems to me that every so often some joint is getting a mild current surge - is that plausible ? Given that we know conductors got cooked eateries in the year "sooty"
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If a high voltage exists across two interconnected lengths of metal and the point of interconnection is not a perfect zero impedance then, given a sufficiently high potential difference, a significantly large current would flow at the point of interconnection.
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And the point of interconnection having a non-zero resistance would suffer Joule heating I 2R .
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Exactly. And with the interconnection being a gel-crimp (i.e. a plastic gubbins filled with petroleum jelly) a localised pyrotechnical event can be virtually guaranteed.
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So the source of the potential difference that creates the current flow could be earth potential rise / ground potential rise around the edges of the thunder cloud ? Slow cooking, relatively speaking ?
Or if there’s a surge induction in the conductor due to a magnetic field - is that plausible?
But why those tones selectively and not others ? And downstream-only? It’s always exactly the same pattern, just the depth of it changes. Never seen this phenomenon until this year.
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So the source of the potential difference that creates the current flow could be earth potential rise / ground potential rise around the edges of the thunder cloud ? Slow cooking, relatively speaking ?
Or if there’s a surge induction in the conductor due to a magnetic field - is that plausible?
I think both cases are valid. The former slowly creeps up on the observer; a significant electromagnetic surge, a big bang, is more obvious.
But why those tones selectively and not others ? And downstream-only? It’s always exactly the same pattern, just the depth of it changes. Never seen this phenomenon until this year.
To me, that is still a mystery. I still have not managed to dream-up any (even remotely plausible) explanation.
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It seems to me we have to ask "what kind of electrical circuit gives us a picture like that?".
What does a bridged tap look like? - I can’t remember.
And what does a partial reflection look like ? - with interference between the outward and reflected waves
Interference scenarios give a frequency-dependent response, no?
I found this - https://patents.google.com/patent/US6177801B1/en
I think that some highly nonlinear circuit element(s) would perhaps produce a picture that is not so well-known; perhaps that might be a fruitful but extremely difficult avenue to pursue.
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A question: what does it look like in terms of SNRM-vs-tones if you have a lightning surge to an NTE5 or to an SSFP ? Have you had such an event and have you then collected very detailed stats? Or have you had a tweak impacting a joint in your long copper line?
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A question: what does it look like in terms of SNRM-vs-tones if you have a lightning surge to an NTE5 or to an SSFP ? Have you had such an event and have you then collected very detailed stats? Or have you had a tweak impacting a joint in your long copper line?
I have not, fortunately, experienced any such event so I have no idea what would be seen in a post-event harvest of a circuit's statistics snapshot.
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Burakkucat suggested a very interesting idea to me. What if phone calls to the line might be able to clear the faults ? Due to the high peak ring voltage, I assume. Alternatively, what if the output from some of their JDSUs’ test sequences might be capable of clearing a fault?
Has any engineer ever seen anything like that?