Kitz Forum

Broadband Related => ADSL Issues => Topic started by: Weaver on July 09, 2020, 01:13:18 AM

Title: Line 2 irregular squarewave in upstream SNRM
Post by: Weaver on July 09, 2020, 01:13:18 AM
In line #2 I have been getting the upstream SNRM variation shown below for a long while now. The graph below coverrs the period 7-8 July 2020. Upstream is the upper, green trace shown below, varying from 4.2 to 6.7 dB. The lower trace is downstream SNRM. The variation shown below is pretty typical:

(https://i.postimg.cc/v8CqXJv2/0-A9-EA321-F744-4-FC6-88-BA-AEFCB97-DF7-D1.jpg)

The times of the transitions are not so easy to read off this graph; leaving out the lesser spikes, they are:

(high)  - ↓ falling:2020-07-07 02:19:00
   ↑ rising:2020-07-07 05:24:00  - ↓ falling:2020-07-07 09:57:40
   ↑↓ up-down spike:2020-07-07 12:15:40 ↓
   ↑ rising:2020-02-08 02:16:50  - ↓ falling:2020-07-08 08:35


Line #3 has a variation in upstream too, but the height is double at > 4 dB and is just a straight squarewave with a 24-hr period, there is just one up-going transition per day.

Have discussed line 3’s variation at length in earlier threads. I find line 2 even harder to understand because the times of transitions don’t seem to have an obvious explanation. If the explanation is that noise is being generated while some piece of equipment is switched on, then why would something be switched on/off at those times in the day?
Title: Re: Line 2 irregular squarewave in upstream SNRM
Post by: burakkucat on July 09, 2020, 03:16:00 PM
Would an auto-switching sewerage pump be a possibility? (Obviously not in Heasta but somewhere on the route to Harapul and then on to Broadford.)
Title: Re: Line 2 irregular squarewave in upstream SNRM
Post by: Weaver on July 09, 2020, 10:08:44 PM
I’m not familiar with this equipment. A device whose operation is triggered by some state sensor input, such as a level sensor, would fit our requirements for guilt perfectly here. A good suggestion.

There remains as usual the mystery of “why only line x?”: Line 1 and line 4 have no upstream SNRM variations and line 3 has a diurnal simple, straightforward square wave variation with a 24-hour period, as discussed many times earlier. (Mind you, today line 3 has had no square wave at all.) How can the location/physical placement of the copper lines be so very different?

I’m presuming that at least nowadays I do have an E-side, although I may have had no such thing at all given that we thought I had EO lines. When I say E-side I’m thinking of an arrangement with extremely long D-side though. I’m also assuming that when FTTC became available in the Broadford area that could be the first time I ever had a PCP (?) so it may be that a lot of things changed and that would have been about two or three years ago.

In that E-side run, there is a school, a supermarket and petrol station, a hotel and some houses and one or two shops. There is a pub/restaurant ‘The Claymore’ near to the PCP, although I would say that that is nearer to the D-side. So there are opportunities to park various kinds of electrical equipment.
Title: Re: Line 2 irregular squarewave in upstream SNRM
Post by: burakkucat on July 09, 2020, 11:26:31 PM
Of your four lines, I believe only the fourth - the last to be installed - is split into an E- & D-side. I recall that a pair diversion was mentioned . . . possibly involving the PCP near the Claymore restaurant. The other three lines are EO.
Title: Re: Line 2 irregular squarewave in upstream SNRM
Post by: Weaver on July 09, 2020, 11:52:38 PM
Ah, thank you. My memory failed me. Line #2 is the most recently installed, fyi. The chronological order is #1, #3, #4, #2, and the reason that it’s so confusing is something to do with ‘slot’ #2 at one time being originally taken by a 3G SIM or similar iirc. The internet access links or pseudo-‘lines’ were numbered in increasing order starting from 1. Anyway, for many years the ‘lines’ were numbered 1, 3, 4 in chronological order and #2 was free. Much later on, ‘slot’ 2 became freed up and so that number was finally available for allocation for a copper line a couple of years ago (was it?).

I don’t understand the topology of what happened around that time - perhaps you have an opinion.
Title: Re: Line 2 irregular squarewave in upstream SNRM
Post by: burakkucat on July 10, 2020, 01:01:48 AM
Sorry for causing any confusion. In my previous post I was referring to the chronological order of the deployment of the lines. So the first three were - or still are - EO. The last one, the one most recently deployed, the one that makes up your quartet, required some ingenuity to divert a pair from one cable to another. I believe that is the one connected via the PCP (by the "Claymmore").

Looking in my notes, I can also see the telephone numbers and BBEUIDs for the four lines. Omitting the confidential information from the list it reads --
Title: Re: Line 2 irregular squarewave in upstream SNRM
Post by: Weaver on July 10, 2020, 01:34:31 AM
We are in agreement.