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Author Topic: asbokid  (Read 599 times)

konrado5

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asbokid
« on: August 01, 2018, 05:11:22 PM »

It's a shame asbodkid is absent on this forum for years. I think he could help diagnose my unusual Hlog graphs and other unusual characteristics of my circuit. He has very deep technical knowledge.
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kitz

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Re: asbokid
« Reply #1 on: August 02, 2018, 10:43:23 AM »

Why?  'Asbokid' hasn't been on the broadband scene for years and won't be coming back.  I really am not sure what you think he would be able to tell you what has already been said several times by b*cat, myself and others.

I know you don't have the perfect hlog - There's a trough at ~ tone 55 which at face value could indicate a bridge tap length of 675 foot (205m).   However there's no accompanying sign of signal reflection or the trough (dips) pattern repeating.  Whilst lack of a repeating pattern can sometimes occur if the source of the bridge tap is several hundred meters from the CPE, but based on the steepness of the angle of your trough I would usually expect to see a repeat pattern emerging if it was a bridge tap.

Hlog can show up several things not just bridge taps but anything else that could attenuate the line such as a capacitive issue, but it doesn't look like that either because its a dip rather than a slope off.

Not all hlogs are straight line perfect..  and there's plenty of examples within technical journals whereby parts of the spectrum despite displaying bumps are considered within the realms of normal operation.

What you need to bear in mind is that hlog is one set of stats taken during the initialisation stage of the sync process and whilst it may be able to give an indication of the length of any possible bridge tap, these figures on their own are unable to provide a more detailed diagnostic as to where the fault may actually lay.

You are asking the impossible -  How you expect anyone other than an engineer who is able to physically examine the loop and use other diagnostic tools such as a JDSU is beyond me.

A JDSU can take the line into diagnostic mode to get other comparative tests which aren't available during modem showtime.  These are then overlaid and compared to the [simple] hlog.  It has a specially written program function which uses propitiatory algorithms and projections from certain points on curves, peaks and troughs to determine the type of defect and also at what distance.   You just cannot get that type of detailed info from the hlog produced from your modem alone.

Jeeze wept are you are basically asking someone to write a a program which uses several complicated algorithms, when we don't even have some of the required data sets.    That's what tools like the JDSU is for and why they are so expensive.   Even if you did have a JDSU, you can't then go physically looking at the joints which belong to the network operator.

You've been asking the same questions for years, b*cat and I and many others have helped all we can, but if you want a more definite answer then you really will have to get an engineer out to run further tests and physically examine the loop and joints. 
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konrado5

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Re: asbokid
« Reply #2 on: August 02, 2018, 06:05:47 PM »

I know you don't have the perfect hlog - There's a trough at ~ tone 55 which at face value could indicate a bridge tap length of 675 foot (205m).
As I know burakkucat has excluded that it is caused by bridge tap. Furthermore, I've discovered what causes this trough. There are measurement errors. On the other circuit I've noticed small dip on the same tone (hlogdertyhwithmarked55tone.png). Furthermore, some time I've had anomalous synchronization with more shallow through per 55 tone. I've discussed with burakkucat in this thread.
https://forum.kitz.co.uk/index.php/topic,17093.msg322530.html#msg322530
Quote
You are asking the impossible -  How you expect anyone other than an engineer who is able to physically examine the loop and use other diagnostic tools such as a JDSU is beyond me.
I believe if somebody with very deep technical knowledge will be cooperating with me it is possible to discover a kind of impairtment wihout JDSU or similar tools. I am confirmed with my belief by the fact that I've discovered one thing: what causes through per tone 55. I've still not disovered what causes 210 dip. Burakkucat has excluded it is a bridge tap.
https://forum.kitz.co.uk/index.php/topic,18164.msg329056.html#msg329056
Quote
You've been asking the same questions for years, b*cat and I and many others have helped all we can, but if you want a more definite answer then you really will have to get an engineer out to run further tests and physically examine the loop and joints.
I've done much progress but I still haven't got definite answer. However I believe that definite answer is possible.
« Last Edit: August 02, 2018, 06:08:15 PM by konrado5 »
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burakkucat

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Re: asbokid
« Reply #3 on: August 02, 2018, 06:59:35 PM »

Think about the plots, their scaling and the granularity of the data that is being used to generate the curve.

(The word "curve" has a specific usage when data is being plotted. A perfectly straight line can correctly be called a "curve".)

Your Hlog plots are generated by using points in a two-dimensional rectangular Cartesian coordinate system. The abscissae occur at a regular 4.3125 kHz spacing. Nothing we can do will allow the data to be "harvested" with a smaller spacing. (The precision of every abscissa is very good, it is 0.5 Hz.) Think about that 4.3125 kHz spacing . . . that width is greater than the audio band-width of a standard telephone! The "harvested" data give us values for the ordinates to four decimal places on a logarithmic scale. The ordinates spacing and precision are both good. Even if you used a different utility, a different method, to plot the Hlog curves you will not be able to escape the granularity of the abscissae. Just look at the Hlog plot you have attached . . . It is possible to see the granularity by the stepwise appearance of the plot. You keep mentioning sub-carrier number 55. I look and see nothing other than experimental error and a limitation of the method by which the data points are generated and are subsequently plotted.

I have nothing else to say on this subject. Please do not bring it up again.

Finally, for good measure, I attach a copy of the Hlog plot for my circuit which was generated earlier today. To the limits of the data precision and the mode used to generate the curve of the plot I see nothing other than a perfectly normal representation of the transfer function, loosely the attenuation versus frequency (with 4.3125 kHz spaced abscissae), for an xDSL circuit operating in G.992.3 mode.
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Black Sheep

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Re: asbokid
« Reply #4 on: August 02, 2018, 07:39:18 PM »

You are trying to achieve perfection, K5 .... but we are not in a laboratory-controlled environment !!.

That is why here in the UK (and I'd wager Poland too ??), there is a term called 'Cone of Acceptance' that ensures engineers and ISP's alike, don't throw good money after bad trying to appease end-users with the most negligible of issues.

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kitz

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Re: asbokid
« Reply #5 on: August 02, 2018, 08:25:37 PM »

I have nothing else to say on this subject. Please do not bring it up again.

I think that just about sums it up.
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