Swapped to ADSL2 Noise now 2147483647 dB?

[weemee]

Hi all,

swapped to ADSL2 a few days ago.  Was getting about 7500 Kbps, now getting about the same but with a larger upload.  Slightly disappointed with this as I was expected to get at least 10 or so - but never mind!

Anyway I'm posting as my connection was terrible this morning, I reset the router and it is moving again but the router is now reporting the following:

Operation Data    Upstream    Downstream
Noise Margin    5 dB          2147483647 dB
Attenuation    23 dB    21 dB

Now I know that the downstream can not be right.  I've never seen it do this before, but restarting the router does not seem to clear it.

Any ideas?  Firmware bug maybe or could it be a sign of something?

Thanks

[Rik]

Netgear? That's a sign that the noise margin has dropped into negative territory (theoretically impossible).

Many people are finding that they gain little or nothing in downstream speed I'm afraid.

[Bill]

(theoretically impossible).

Nooo...  if the signal level drops below the noise level then (in db terms) the margin is negative. Unlikely the router will maintain sync for long under those conditions, but some can manage -1db or -2db. My old Linksys could... pretty rubbish router in many other ways, but boy, could it hold sync 

[Rik]

With Netgears, Bill, I often wondered if it was a fault in their reporting as the NM did tend to fade over time, something I don't see with, for example, the 2700.

[Bill]

Netgears (and some others I think) certainly have a firmware bug that causes them not to report negative numbers properly, haven't heard about the NM fading over time.

I've found they can run very hot and integrated circuits don't like that much, so it could be one of the ICs at the "front end" is gradually degrading and introducing its own noise into the circuit... just a guess though.

[Rik]

There was a thread on the subject on TB some 2-3 years ago. It was Andrew, iirc, who indicated the issue. The 2700, otoh, has a fault in the reporting which causes it to report negative power output with some MSANs. 

[weemee]

Netgear? That's a sign that the noise margin has dropped into negative territory (theoretically impossible).

Many people are finding that they gain little or nothing in downstream speed I'm afraid.

Not a Netgear, but a 3COM unit.  It's a few years old now.  I'll see what the Sync does tommorow.

[Rik]

Another good guess bites the dust. It's the same problem, though, mis-reporting a negative number. Keep an eye on it. What are your sunc speeds, up and down?

[weemee]

Another good guess bites the dust. It's the same problem, though, mis-reporting a negative number. Keep an eye on it. What are your sunc speeds, up and down?

Hi,

Had a check this morning.  Still as it was yesterday in respect of the noise.

Stream Type    Actual Data Rate
Up Stream          1085 (Kbps.)
Down Stream    7588 (Kbps.)

Cheers

[Rik]

That's low for your attenuation. Do you have an NTE5 master socket, the type where the bottom part of the faceplate can be removed? If so, can you try connecting the router to the test socket which is then revealed?

[weemee]

That's low for your attenuation. Do you have an NTE5 master socket, the type where the bottom part of the faceplate can be removed? If so, can you try connecting the router to the test socket which is then revealed?

Hi again,

Yes I managed to connect to the master socket.  Pretty much the same, the router did (before i disconnected) lower the profile again:


----------
Stream Type    Actual Data Rate
Up Stream    1085 (Kbps.)
Down Stream    6653 (Kbps.)
---------
Operation Data    Upstream    Downstream
Noise Margin    5 dB               22 dB
Attenuation    23 dB               20 dB

Any suggestions?

[Rik]

I'm wondering whether the router is swapping u/s and d/s stats, the u/s looks much more like a d/s result and vice versa. I'd suggest you call support, they can test the line and see the figures from their end. It looks to me, though, that your line is noisy on the BT side. TBH, the chances of getting BT to do anything about it are slim though.

[weemee]

I'm wondering whether the router is swapping u/s and d/s stats, the u/s looks much more like a d/s result and vice versa. I'd suggest you call support, they can test the line and see the figures from their end. It looks to me, though, that your line is noisy on the BT side. TBH, the chances of getting BT to do anything about it are slim though.

I'm temped to change the router as it's a little on the old side anyway - didnt support ADSL2 until a firmware update which was a number of years ago.  Any recomendations, no need for WIFI?

I'm also going to invest in a some new microfilters, possibly those ADSL nation ones I've heard mentioned a few times (XF1-E?).  See if these changes make any difference?

Thanks

[Rik]

I'd certainly recommend the ADSL Naton filters, I've been using them for a couple of years or more and they're the best I've found (as much as it's possible to compare filters). With routers, Netgear, Speedtouch or the 2-Wire 2700 (eBay, around £15 delivered) would be my choices. Most nowadays have wireless, though you can still find them without.

[Sebby]

I agree with Rik about ADSL Nation filters. A Netgear DG834Gv4 seems to be a good router choice at the moment.

[weemee]

Hi all,

Thought I'd post back with an update.  Havent changed anything yet, but here is an update on the sync rate:

Data Rate
Stream Type    Actual Data Rate
Up Stream          1085 (Kbps.)
Down Stream    15065 (Kbps.)

Operation Data    Upstream    Downstream
Noise Margin    5 dB            2147483647 dB
Attenuation    23 dB    21 dB

So it looks like the sync will be supported higher, I just need to work out why it isn't very stable!

Thanks

[Rik]

Essentially because the noise margin is low (-2db I think).

[Gary]

I agree with Rik about ADSL Nation filters. A Netgear DG834Gv4 seems to be a good router choice at the moment.

I still have one of those as a spare router Sebby 

[weemee]

Essentially because the noise margin is low (-2db I think).

Agreed.  I'll dig out a new router and see if it cures it!   I shall report back later.

[Sebby]

I still have one of those as a spare router Sebby 

Want to sell it?

[weemee]

Hi all,

A quick update.  I've purchased a new router (as suggested the V4 834G by Netgear).

Here are the new line stats for the initial setup:

DownStream Connection Speed	15323 kbps
UpStream Connection Speed	795 kbps

ADSL Link	Downstream	Upstream
Line Attenuation	24.5 db	10.9 db
Noise Margin	4.4 db	5.4 db

Any thoughts?  Connection is now usable for most sites, but still operating below par.

Thanks

[Rik]

What are your sync speeds now, and why do you feel it's operating below par?

[weemee]

What are your sync speeds now, and why do you feel it's operating below par?

Hi,

Sorry I put them in the post above in edit mode.

It's currently downloading at 10.5kb/s.  highest I can get it is about 100kb/s.

Thanks

[Rik]

It sounds like you have the dreaded BT under-dimensioning, which has afflicted a few of us. Let support know, and let them have some BT speed tests run at various times of day. They can then chase BT down on the issue.

[weemee]

It sounds like you have the dreaded BT under-dimensioning, which has afflicted a few of us. Let support know, and let them have some BT speed tests run at various times of day. They can then chase BT down on the issue.

Errr 

Can you clarify what this means please?

Thanks