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Costant speed decline because of crosstalk

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Plusnet Help Team
Plusnet Help Team
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Registered: ‎21-04-2017

Re: Costant speed decline because of crosstalk

Haha no problem. Smiley
If this post resolved your issue please click the 'This fixed my problem' button
 Anoush Mortazavi
 Plusnet Help Team
riccardo2
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Registered: ‎19-02-2017

Re: Costant speed decline because of crosstalk

From a report I see the only problem found is some interference not from my house, but the "service impact" seems to say they are not a real problem.

 

Interference Pattern Regular Interference Observed Daily
Service Impact No Impact Observed
Interference Duration Longest Occurrence From12:15to04:15
Interference Location Customer Premise
Interference Observed In Days 5
Home Wiring Problem Not Detected

 

Other things... are all OK

 

Bridge Tap Not Detected
Radio Frequency Ingress Not Detected
Repetitive Electrical Impulse Noise Not Detected
Cross Talk Not Detected
Estimated Line Length In Metres 530.1
Upstream Rate Assessment Low
Downstream Rate Assessment Low

 

Basically it's all OK:

- no crosstalk,
- no important noise,
- router in the test socket (so to speak because there is only 1 VDSL socket and the test is done detaching the rest of the wiring),

but the sync is low compared to 3 years ago, both with the hub one or the Openreach modem.

 

Anyway I think SNR 6 and a sync speed of 42mbps over 530m of cable it's a bit noisy. I've had an ADSL in sync at 19mbps with SNR 13 over a similar lenght. The VDSL frequency is higher to more subject to noise and crosstalk... but it was better.

Let's ditch the problem... the next April the cabin will be upgraded to 300mbps and something will happen...

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Registered: ‎10-06-2010

Re: Costant speed decline because of crosstalk

If the 300Mb upgrade is G.fast, you will probably gain nothing (directly), because you are very likely to be too far from the cabinet to get G.fast. If it's Virgin Media building their network or someone building a full fibre network, obviously that's different.

Plusnet Help Team
Plusnet Help Team
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Registered: ‎21-04-2017

Re: Costant speed decline because of crosstalk

Personally if it were me I’d go for the engineer as it may just be a simple problem which can be fixed but it’s your decision at the end of the day. Smiley
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 Anoush Mortazavi
 Plusnet Help Team
riccardo2
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Registered: ‎19-02-2017

Re: Costant speed decline because of crosstalk

If the 300Mb upgrade is G.fast, you will probably gain nothing (directly)

g.fast on 500m should be around 100mbps. Basically I would probably end up with the speed I should have with the current contract: 76mbps

But I'm not interested in g.fast as much as vectored VDSL2 to cut off the main problem: noise. At my distance, probably vectored VDSL2 is faster than g.fast.

 

Personally if it were me I’d go for the engineer as it may just be a simple problem which can be fixed but it’s your decision at the end of the day. Smiley

Probably I'll give it a try, but later because I'm going to place an order to switch to another ISP in 3 days so could be a complication at this point.

NB: I'm not switching because I don't like PS or to get a better service, it's simply because the same product costs 12 pounds/month or less. TT with voucher comes at 22/month. Vodafone at 22.99 but if the router doesn't sync at 49.6 (good luck with my line! Grin) there is discount of 15% (no engineer required, they don't even try to fix it unless the customer ask for it). So in my case Vodafone 63 would come for sure at 19£ that is basically for free since it's the price of the line rental + a couple of pounds for the FTTC.

The last time I renewed with PS I didn't get a good price: it was worse than for a new customer and 24 months instead of 18. Currently I'm paying 32.98 against the 27/28 of a new customer, so, no offence, but I don't even try this time. The top UK ISPs force us to become the so called "Serial switcher". Not switching always results in a loss of money. So they get what they want: a continuum of mass migration (and probably this doens't even result in a better turnover). I can't change the world so I must adaprt to this crazy life.

Plusnet Help Team
Plusnet Help Team
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Registered: ‎21-04-2017

Re: Costant speed decline because of crosstalk

Thanks for getting back to us @riccardo2 

No problem, if you'd want to stay with us I'd be happy to arrange someone to call you back to discuss recontracting? 

You're also right that when there's an open cease/migration order we'd struggle to raise a fault with Openreach.

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 Anoush Mortazavi
 Plusnet Help Team
riccardo2
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Re: Costant speed decline because of crosstalk

OK thanks.

Just out of curiosity, for the sake of the argument and knlowledge... This morning there is a pretty bad SNR

 

4. Board version: Plusnet Hub One
5. DSL uptime: 13 days, 00:39:56
6. Data rate: 15322 / 42720
7. Maximum data rate: 14250 / 47889
8. Noise margin: 5.2 / 5.5
9. Line attenuation: 22.1 / 16.8
10. Signal attenuation: 21.9 / 16.8

 

SOLUTION:
As usual, when I use the line heavily for few minutes and look again at the SNR, it has improved. E.g in this case I've made a speed test with 200MB

 

6. Data rate: 15322 / 42720
7. Maximum data rate: 14390 / 48315
8. Noise margin: 5.3 / 5.9
9. Line attenuation: 22.1 / 16.8
10. Signal attenuation:

21.9 / 16.8

 

After 400MB

 

6. Data rate: 15322 / 42720
7. Maximum data rate: 14483 / 48538
8. Noise margin: 5.4 / 5.9
9. Line attenuation: 22.1 / 16.8
10. Signal attenuation: 21.9 / 16.8

 

After 800MB

6. Data rate: 15322 / 42720
7. Maximum data rate: 14333 / 48674
8. Noise margin: 5.3 / 6.0
9. Line attenuation: 22.1 / 16.8
10. Signal attenuation: 21.9 / 16.8

 

after 2GB

6. Data rate: 15322 / 42720
7. Maximum data rate: 14470 / 48801
8. Noise margin: 5.4 / 6.0
9. Line attenuation: 22.1 / 16.8
10. Signal attenuation: 21.9 / 16.8

 

The more I use the line the better (until it reach 6.0/6.0 that is probably the SNR target).

NB: this happen in the same DSL uptime session and in the range of few minutes.

It happens ALWAYS. It's a rule I've tested an infinite number of times.  I've not tested the time of decay, in the sense of how long it take to get worse not using the line. When the line is not in use the noise arises. When I "smash" the line the SNR improve of some points, e.g. from 5.5 to 6

The bad thing is that with the passing of time the target SNR 6 is bound to a lower sync speed.

Is that normal? Is there a kind of logic by design in the DSLAM/DLM? Or it is some electronic component in the cabinet not working properly? The signal cannot cause evaporation of humidity in junctions etc.,but can have an impact on the DSLAM board because the processor/RAM there work more (= more heating on the board and probably in the cabinet).

Plusnet Help Team
Plusnet Help Team
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Re: Costant speed decline because of crosstalk

No problem @riccardo2 

The fluctuation in the SNR is perfectly normal as most lines will fluctuate to some degree.

As you already know our recommendation is an engineer visit to look into this further.

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 Anoush Mortazavi
 Plusnet Help Team
riccardo2
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Re: Costant speed decline because of crosstalk

Of course, but that doesn't seems to be ordinary random fluctuation because the SNR improves for sure (when it is above the target value), every time, after a big download, e.g., 1GB. Once improved it never get back for a while (I haven't measured the time it takes before falling back, but I think hours).

This is not a complain or a request for fixing, it's simply curiosity. Maybe it's a DSLAM logic to manga noise/priority or it's just a problem on the DSLAM card my line is connected to.

Is someone experiencing the same thing or it's just me?

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riccardo2
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Registered: ‎19-02-2017

Re: Costant speed decline because of crosstalk

How ISP calculate the minimum guaranteed speed? With the "last max speed seen" on the DSLAM?