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Bitloading tones missing

Sunzz
Grafter
Posts: 72
Thanks: 2
Registered: 26-09-2016

Bitloading tones missing

Does anyone know why im missing tones between 2000 - 2750 ? no wonder my upload speed is 3 mb lmao TongueBitloading-2016-12-08-14.24.11.pngQLN-2016-12-08-14.24.11.pngSNRpertone-2016-12-08-14.24.11.pngSNRMperbandUpstream-2016-12-08-14.24.11.png

6 REPLIES
Andrue
Pro
Posts: 775
Thanks: 90
Fixes: 1
Registered: 12-01-2015

Re: Bitloading tones missing

The second graph is a Quiet Line Noise graph. It's showing that something else ('other' ) was occupying the space at the time the connection was established. So the modem couldn't use those tones. According to the Kitz site this appears to be 8.6MHz to 11.8MHz. 

Make of that what you will :-/

Sunzz
Grafter
Posts: 72
Thanks: 2
Registered: 26-09-2016

Re: Bitloading tones missing

Bump Sad could i get an admins/mods view on this pleasssssse Smiley

Andrue
Pro
Posts: 775
Thanks: 90
Fixes: 1
Registered: 12-01-2015

Re: Bitloading tones missing

I'm not sure they'll be able to shed any more light on it than I did. It's something local to you and I don't even know if Plusnet have access to that level of information. All we can say is that your cabinet and/or your modem decided not to use those frequencies the last time they negotiated a connection. You could ask on a technical forum like Kitz or Thinkbroadband to see if it's been seen before. You could also ask on a radio enthusiasts site to see if anyone there knows of something that could take out those frequencies in your immediate area.

But asking PN for an explanation is a bit like asking Ford to explain why there are potholes outside your house Smiley

Moderator's note by Mike (Mav): Full quote of preceding post removed as per Forum rules.

Sunzz
Grafter
Posts: 72
Thanks: 2
Registered: 26-09-2016

Re: Bitloading tones missing

Asking ford about pot holes? lmao thats completely different. I have to go through plusnet to get to BT. Any time i try to contact BT it said to go through your internet service provider. No plusnet admins/mods have a clue why these bit tones are missing?

Andrue
Pro
Posts: 775
Thanks: 90
Fixes: 1
Registered: 12-01-2015

Re: Bitloading tones missing


Sunzz wrote:

Asking ford about pot holes? lmao thats completely different.

No, not really. Ford aren't responsible for the condition of the roads outside your house and nor are Plusnet responsible for the condition of your phone line or the decisions that the DSLAM makes.

 

The only difference is that Ford would refuse to get involved whereas Plusnet might be able to ask openreach to investigate the issue if the impact is severe enough. The important point here is that Plusnet are not responsible for your telephone line or the DSLAM. That's another company entirely. PN simply can't get the information you want themselves. Nor should we expect any of their staff to have the knowledge about DSL that you require because they don't operate any DSL equipment.

 

If the performance of your line is sufficiently low as to warrant being labelled as a fault then PN can ask openreach to take a look. openreach may (probably won't) give PN an explanation of the problem. More likely they will eventually respond with one of the following:

 

* Fixed it.

* Seems fine to us.

* Can't fix it, sorry.

 

Missing tones implies radio interference. Radio interference can come from almost anywhere and anything. Most sources are outside of openreach's control (maybe one of your neighbours is a keen ham radio operator). My understanding of how DSL works suggests that it's unlikely to be a fault at the DSLAM. So what we're left with is 'for some reason those bits are not being used'.

All you can do is raise a fault and wait for the outcome.

Oh and maybe try a different modem although I'm sceptical that any kind of electronic fault could cause this behaviour.

Oh and ask in some technical forums like the ones I mentioned. A lot of keen amateurs like me have picked up technical details here and there. It rarely makes any practical difference but sometimes just knowing what the problem is makes it easier to accept the consequences.

Moderator
Moderator
Posts: 18,115
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Registered: 06-04-2007

Re: Bitloading tones missing


Sunzz wrote:

No plusnet admins/mods have a clue why these bit tones are missing?


Moderators are customers just like yourself with no access to Plusnet or BT systems.

Forum Moderator and Customer
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