Zero Noise Margin

Since first thing this morning, my router has been reporting a zero for the noise margin. I have not lost sync and the connection has not dropped. My connection speed and real download speeds have not dropped either.
I thought a connection could not be maintained with a zero noise margin. Is this likely to be glitch from the netgear 834 router?, or is this something I should not worry about?
Thanks for any insight.

Since the last engineer visit, and prior to this morning, my noise margin has been a fairly stable 7 or 8 at all times of the day. Then this morning I noticed it had dropped to zero. I have noticed no change in download performance and I've run a speed test a couple of times and I'm getting my normal stats.
I know in the past, that a temporary noise margin drop to zero would sometimes mean a loss of sync, but this has been at zero all day so far with no apparent ill effects. That's why I thought it might be a glitch.
I'm reluctant to power down the router to see if that would change anything. My line is the most stable right now that it has been in months, and I don't want to mess that up unless it is absolutely necessary.
Here are my router stats. I can't run the BT speedtester at the moment, as I'm running a backup to a network drive right now.
System Up Time 103:48:04
Port
Status
TxPkts
RxPkts
Collisions
Tx B/s
Rx B/s
Up Time
WAN
PPPoA
546113
761091
0
174
2484
103:47:26
LAN
10M/100M
1611459
1803285
0
2673
739
103:48:00
WLAN
11M/54M
359075
146543
0
622
34
103:47:51
ADSL Link
Downstream
Upstream
Connection Speed
1280 kbps
448 kbps
Line Attenuation
59 db
15.5 db
Noise Margin
0 db
14 db

Similar Messages

Difference between noise margin and noisy line

Hi
This issue has always bugged me. Am transferring to BT Infinity next week from Sky and have mixed feelings. We live a fair way from the exchange so line attenuation is a problem but we mange to get 3.5-4Mb with absolutely zero outage using the Sky unlimited package. Our current router stats are posted below and I woud be grateful for your interpration of the noise margin figs. Is the 7db download commensurate with a quite and stable connection that bodes well for Infinity? I'm curious cos our phone line is noisy with much background niose despite the fact that we don't have any fancy gadgets and use filters just about everywhere.
I'd just like your views on noise on the line versus noise margin for broadband and how each might impact on Infinity when we're connected next week.
Many thanks for your time.
Router StatisticsSystem Up Time: 05:44:16
Port Status TxPkts RxPkts Collisions Tx B/s Rx B/s Up Time
WANPPPoA
403055
369851
0
14261
13203
05:42:39
LAN100M/Full
370239
415781
0
13527
14890
05:44:11
WLAN11M/54M
8864
0
0
150
0
05:43:58
ADSL Link Downstream Upstream
Connection Speed4093 kbps
796 kbps
Line Attenuation51 db
28 db
Noise Margin4 db
14 db

Enter your attenuation here http://www.kitz.co.uk/adsl/max_speed_calc.php
Results are approximate
If any post helps tick the star box on the left
Just cause Im paranoid dont mean they are not out to get me

Question about Noise Margin and Line Attenuation a...

1.       For several years I have had a BT telephone line. From the utilities provided by http://www.kitz.co.uk/adsl I find that I am connected to the Exchange at Merton Park (BT Code: LSMEPK) Distance:-   Direct:   960 metres (appx)* By Road: 1.29 km. Exchange Status ADSL enabled: March 30, 2000 DSL Max enabled:   March 30, 2006 SDSL enabled : Enabled 21CN due : (PSTN) N/A 21CN WBC (Broadband)   Enabled 15.02.09
2.       I previously had broadband from UKOnline and used a Speedtouch 570 adsl modem. I was paying £9.99 for a speed of 1MBit/s – in practice 700K – which was fine for most purposes but BBC iplayer did struggle a bit. UkOnline has been taken over by SKY so I switched to BT Total Broadband Option 3 in mid December, and initially used the Speedtouch 570 as there were delivery delays on BT Home Hub 2.0 due to weather conditions. Speed was initially very good but did not measure it.
3.       After Xmas I set up the BT Home Hub and ran a speed test - the profile was 2.5MBit/s. I was disappointed to get less than 3Mbit/s which is needed for BBC iplayer HD.
ADSL line status
Connection information
Line state Connected
Connection time 0 days, 2:26:57 ------> 6th January 2011
Downstream 2,268 Kbps
Upstream 440 Kbps
ADSL settings
VPI/VCI 0/38
Type PPPoA
Modulation ITU-T G.992.5 ---à this apparently means ADSL2+
Latency type Interleaved
Noise margin (Down/Up) 15.7 dB / 31.9 dB
Line attenuation (Down/Up) 27.0 dB / 9.7 dB
Output power (Down/Up) 0.0 dBm / 12.7 dBm
Loss of Framing (Local) 22
Loss of Signal (Local) 3
Loss of Power (Local) 0
FEC Errors (Down/Up) 6512 / 0
CRC Errors (Down/Up) 0 / 2147480000
HEC Errors (Down/Up) nil / 0
Error Seconds (Local) 2
4.       As part of the “slow speed wizard” I looked into getting the accelerator plate for my NTE5 split face master socket available for postage only (£1.20) but the web form advised me that if I proceeded with this order the broadband contract would automatically be extended by 12 months. I checked my BT internet account and was surprised to find an email (23rd Dec 2010) advising me that as an Option *1* customer I was in danger of exceeding my usage allowance – which surprised me as I am definitely Option 3. I wondered if I had had the speed throttled. Therefore phoned BT accounts who said the email was a mistake - I am Option 3, also said that accelerator plate was unlikely to make a difference.
5.       I contacted the BT call centre who talked me through various options. Plugging the hub direct into the master socket made no difference. They also ran a line test and said the line was fine.
6.       I therefore browsed the community care forum and find that disappointing speeds are not uncommon. One of the threads mentioned disconnecting the bell wire on the extensions. I follow this advice and removed line 3 on all extensions and then checked the ADSL status on the hub.
ADSL line status
Connection information
Line state Connected
Connection time 0 days, 6:33:45 10th January 2011
Downstream 2,272 Kbps
Upstream 888 Kbps
ADSL settings
VPI/VCI 0/38
Type PPPoA
Modulation ITU-T G.992.5
Latency type Interleaved
Noise margin (Down/Up) 31.8 dB / 14.4 dB
Line attenuation (Down/Up) 27.0 dB / 9.7 dB
Output power (Down/Up) 0.0 dBm / 12.3 dBm
Loss of Framing (Local) 0
Loss of Signal (Local) 0
Loss of Power (Local) 0
FEC Errors (Down/Up) 0 / 0
CRC Errors (Down/Up) 0 / 2147480000
HEC Errors (Down/Up) nil / 0
Error Seconds (Local) 0
7.       This had a dramatic improvement on Upstream speed – and a big change to the noise margin Noise margin which had been (Down/Up) 15.7 dB / 31.9 dB and is now Noise margin (Down/Up) 31.8 dB / 14.4 dB. It did not improve the download speed.
8.       In the following days the BT hub has not been particularly stable with some intermittent loss of wireless connectivity every few hours. Examining the event log I was a bit disconcerted to see alterations to firewall settings had happened (which I hadn’t made) and resets which I am pretty certain I hadn’t made – and a userid login with a name like TR69. Perhaps these are occasioned by the BT speedtester? To be fair I had reset and powered off the hub a number of times in attempt to sort out this problems.
9.       I have switched to a Netgear DG83GT (V1.03.23) for the time being until I have what I can regard as a reasonably fast stabile connection. At the time of writing this has been stable for 20 hours DownStream Connection Speed 2268 kbps UpStream Connection Speed 888 kbps.As stated earlier I would like downstream to be faster.
The perceived wisdom on the forum seems to be that several days of complete stability are required if there is to be any improvement on speed.
10.   If a moderator or anyone with the relevant experience reads this I would be very grateful for answers to the follow questions:
A.      Is the change in the Noise Margin parameter a good thing or a bad thing?
B.      Are the line attenuation figures acceptable for a distance of under 1.5kilometres to the exchange?
C.      Should I be able in theory to get a faster speed i.e. downstream 3Mbit/s?
D.      From the forum it seems to take several days for speed adjustments to be effected or to take effect – is this a technical issue or a policy issue?
Many thanks.
Robert
Solved!
Go to Solution.

Good Morning - it is now 6 days since this posting. During this time there have been 2 resets of the adsl line
Fri, 2011-01-14 03:28:43 - LCP down.
Fri, 2011-01-14 03:28:54 - Initialize LCP.
Fri, 2011-01-14 03:28:54 - LCP is allowed to come up.
Fri, 2011-01-14 03:28:54 - CHAP authentication success
and
Sun, 2011-01-16 16:37:26 - LCP down.
Sun, 2011-01-16 16:37:36 - Initialize LCP.
Sun, 2011-01-16 16:37:36 - LCP is allowed to come up.
Sun, 2011-01-16 16:37:36 - CHAP authentication success
These were not initiated by me - and since noise margins and sync speeds changed as a consequence can I assume that this is evidence of the adaptive process working?
Secondly, as you can see, the noise ratio has vastly improved as have the upstream and downstream sync speeds
        System Up Time 157:54:52
      ADSL Link          Downstream          Upstream
      Connection Speed           11199 kbps           1091 kbps
      Line Attenuation           27.0 db           9.9 db
      Noise Margin           14.8 db           9.2 db
BUT from the BT speedtester, as shown below I seem to be stuck in a banded IP profile of 1750/1091 which is very different from the downstream sync speeds of 11199 Kbps(DOWN-STREAM)
Can BT staff take action to alter this? If they can how do I contact them?
Regards,
Robert
18th Jan 2010
Download Speed    1288 Kbps
0 Kbps   2000 Kbps
Max Achievable Speed
Download speedachieved during the test was - 1288 Kbps
For your connection, the acceptable range of speedsis 800-2000 Kbps.
Additional Information:
Your DSL Connection Rate :11199 Kbps(DOWN-STREAM), 1091 Kbps(UP-STREAM)
IP Profile for your line is - 1750 Kbps
The throughput of Best Efforts (BE) classes achieved during the test is - 2.28:10.77:87.0 (SBE:NBEBE)
These figures represent the ratio while sententiously passing Sub BE, Normal BE and Priority BE marked traffic.
The results of this test will vary depending on the way your ISP has decided to use these traffic classes.
2. Upstream Test: -provides background information.
Upload Speed       896 Kbps
0 Kbps   1091 Kbps
Max Achievable Speed
>Upload speed achieved during the test was - 896 Kbps
Additional Information:
Upstream Rate IP profile on your line is - 1091 Kbps

New phone line and broadband, massive noise margin...

Hi, being a long time DSL stalwart a recent move to a new property has meant I've needed to switch over to ADSL instead and thus far it's proving to be a bit of a mare!
I waited a month for the initial installation engineer who promptly never showed anyway, no bother I thought, the hub turned up and I installed it myself and it promptly didn't work It soon became pretty apparent that the phone line was completely dead even from the test socket. A few phone calls later and the phone line is working much to my delight. The broadband is another story though, initially it still couldn't connect but later in the day it managed to get going. However it's excruciatingly slow with an average of 20 to 30kps throughput and substantial packetloss. Also worth noting is that in this new property, only the master socket actually works, this place has 4 other sockets dotted around all of which appear to be dead, could these be part of the issue? Does using the test socket completely cut these out and rule out bad wiring? Just to add, at 13 hours connected the adsl status is pretty much the same and I couldn't notice anything on the BT line noise test number.
I'm not familar with the workings on ADSL lines but I'm guessing the root of the problem is down to a wildly varying noise margin both up and down. Down fluctuates between ~2 and 20 within a matter of seconds and up gives some numbers that defy belief. Now the line was originally activated on Wednesday, actually kicked into life sometime on Friday and the router has been connected for 13 hours now, whilst it's still early days and things should bed in more, I assume I'm right in thinking I should be alarmed at how bad a line I'm starting out with? And should I be directing my ire at the builders or BT?
Any help and suggestions will be hugely appreciated!
Cheers!
Solved!
Go to Solution.

as it is a newbuild is the master socket inside your home or outside like this
connecting to the test socket will eliminate all your extension sockets and should be your best connection. if you are not in the test socket could you try it and post new stats please
with your attenuation I would expect a connection speed of about 18mb when you get this fiixed
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Please can I have my Noise Margin lowered *again*

Message sent to StephanieG, who was very helpful last time.
Please can I have my noise margin lowered back down to 6 again?
Although it is plugged 24/7 into the test socket, it has crept up again over the last 6 weeks, until another disconnect 10 minutes ago.
Maybe BT would consider, in future HH firmware updates, allowing users to negotiate their own SNR margin, without having to go through this forum?
Cheers,
Tim
ADSL line status
Connection information
Line state
Connected
Connection time
0 days, 0:04:13
Downstream
5,920 Kbps
Upstream
448 Kbps
ADSL settings
VPI/VCI
0/38
Type
PPPoA
Modulation
ITU-T G.992.1
Latency type
Fast
Noise margin (Down/Up)
14.2 dB / 27.0 dB
Line attenuation (Down/Up)
27.0 dB / 17.5 dB
Output power (Down/Up)
19.8 dBm / 12.4 dBm

I think it is unlikely that BT will ever update the HH to allow users to change their noise margin as it would give them even more support issues. If you wish to continue with a latency type of FAST then I suggest you invest in a router that allows you to specify the noise margin. This thread mentions 1 such router - http://community.bt.com/t5/BB-in-Home/Last-chance-saloon-really-Absolutely-fed-up/td-p/77569

How do I find noise margin etc?

Over the past few months my download speed has dropped from around 7M to around 3. Work has been going on since the start of the year to bring FTTC to the area and I assumed that this was to blame. But that work has now finished, although I personally am unable to get upgraded. I think it may now be a case of the Mods resetting my profile, but I can't seen to find the noise margin etc from my hub stats. I use HH4. Can somebody please help me with this?
Solved!
Go to Solution.

Sorry John & IMJolly, I'm not very good at this with my tablet, and have been unable to upload the results I have found, so I will attempt to type them in. Here goes.
Line stats
14.59.00, 24 Jun. (57.460000) DSL noise margin:5.90dB upstream 8.30dB downstream.
14.58.59, 24 Jun. (56.550000) DSL line rate 1084Kbps upstream 3072Kbps downstream
With regards the ADSL checker
Featured Products. Downstream. Upstream Range. Availability
WBC ADSL 2+ Up to 6. -- 4 to 8. Available
WBC ADSL2+Annex M. Up to 6. Up to1. 4 to 8. Available
ADSL MAX. Up to 5. -- 3.5 to 7.5. Available
WBC fixed rate. 2. -- -- Available
Fixed rate. 2. -- -- Available
Hope this is usable for you

High Noise Margin

Hi there,
It seems like my line has been changed to a different profile with the Downlink Noise Margin Target being set to 10dB.
I'd like to have it back to 6dB as before. I've lost over 0.6Mbps and my speeds weren't exactly that high to begin with!
Many thanks!
1. Product Name: HomeHub4
3. Firmware version: v0.07.01.0910-BT (Type B) Last updated 21/1/2015
4. Board version: 01A
5. DSL uptime: 3 days, 09:19:23
6. Data Rate: 711 / 2203
7. Maximum Data Rate: 724 / 2404
8. Noise Margin: 5.5 / 10.3
9. Line Attenuation: 35.0 / 51.5
10. Signal Attenuation: 34.9 / 55.8
11. Data sent/received: 192.8 MB / 3.9 GB
13. BT Wi-fi: No
14. 2.4GHz wireless network/SSID: BTHub4-Z6FQ
15. 2.4GHz wireless connections: Enabled (802.11 b/g/n (up to 144 Mb/s))
16. 2.4GHz wireless security: WPA & WPA2 (Recommended)
17. 2.4GHz wireless channel: Automatic (Smart Wireless)
18. 5GHz wireless network/SSID: BTHub4-Z6FQ
19. 5GHz wireless connections: Enabled (802.11 n (up to 300 Mb/s))
20. 5GHz wireless security: WPA2 Only
21. 5GHz wireless channel: Automatic (Smart Wireless)
22. Firewall: Default
23. MAC Address: 18:
24. VPI/VCI: 0/38
25. Modulation: G.992.3(ADSL2)
26. Latency type: Fast
27. Software variant: -
28. Boot loader: 0.4.3-BT (Mon Jun 9 14:23:56 2014)

Hi HaoForNow,
Thanks for posting and welcome back!
Sorry for the connection problems you were having with your broadband. Great to see everything has been stable over the last 3 days. I'll help reset the profile to reduce the noise margin and push your connection speed in the right direction ^^^
Click on my username and under the "about me" section of my profile you'll see the link to send us your details.
Cheers,
Robbie
BTCare Community Mod
If we have asked you to email us with your details, please make sure you are logged in to the forum, otherwise you will not be able to see our ‘Contact Us’ link within our profiles.
We are sorry that we are unable to deal with service/account queries via the private message(PM) function so please don't PM your account info, we need to deal with this via our email account :-)
If someone answers your question correctly please let other members know by clicking on ’Mark as Accepted Solution’.

Is my downstream noise margin too high?

As you can see from these stats I have an issue with speed at the moment. I have an engineer coming out tomorrow. Is there any direction I can point him in looking at these numbers.
1. Product name:
BT Home Hub
2. Serial number:
+068343+NQ35147172
3. Firmware version:
Software version 4.7.5.1.83.8.173.1.6 (Type A) Last updated 11/03/14
4. Board version:
BT Hub 5A
5. VDSL uptime:
0 days, 11:21:30
6. Data rate:
19999 / 32394
7. Maximum data rate:
21878 / 70147
8. Noise margin:
6.0 / 16.6
9. Line attenuation:
0.0 / 16.0
10. Signal attenuation:
0.0 / 16.0

DLM has capped ur rate.
you may have line problems.
there are some known issues with the HH5.
do you have a openreach modem ?

High noise margins

Hi all, (nearly) a first time poster and am having SERIOUS issues with BT Broadband.
I was with Sky for ages but migrated to BT, I had consistant and steady speeds with Sky of 4.5 to 5.5 mb.
I had a recent loss of connection (towards the end of my 10 day "settling" period) and the full connection went down soon after and 5 days later re-connected me, the line is noisy to the ear, BT have conducted tests and they say all is fine, I even hear the modem noise connecting if I'm on the phone.
I've checked all sockets, am using the master(there is no test socket in my box, there is no "bell" line connected). I'm on the Hartlepool exchange so don;t know if that has been recently upgraded to the 21CN, if so would this cause any of my problems??
I've have checked everything at my end that could cause excess noise, have removed phones, Sky+box etc.. and still a crappy connection, any ideas guys n gals?? Thanks
Stats below:
ADSL line status
Connection Information
Line state
Connected
Connection time
0 days, 00:00:31
Downstream
575 Kbps
Upstream
888 Kbps
ADSL Settings
VPI/VCI
0/38
Type
PPPoA
Modulation
G.992.3 Annex A
Latency type
Interleaved
Noise margin (Down/Up)
12.5 dB / 9.6 dB
Line attenuation (Down/Up)
49.1 dB / 27.8 dB
Output power (Down/Up)
4.4 dBm / 1.3 dBm
Loss of Framing (Local/Remote)
0 / 0
Loss of Signal (Local/Remote)
0 / 0
Loss of Power (Local/Remote)
0 / 0
FEC Errors (Down/Up)
0 / 0
CRC Errors (Down/Up)
0 / 32
HEC Errors (Down/Up)
0 / 0
Error Seconds (Local/Remote)
0 / 0

when you say the line is noisy have you tried the quiet line test preferably with a corded phone in master socket - dial 17070 and option 2 - you should hear nothing
your exchange has been upgraded to 21CN and you are currently on adsl2 with modulation of 992.3
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Can anyone help? High noise margin and low sync sp...

Hi all,
just registered on the forum so this is my first post. Hopefully someone out there can help.
I transferred my broadband to BT from Sky. With Sky my sync speed was around 4000kbps and download of about 3500kbps. I had a Netgear router with Sky but for some reason every day or so my sync speed dropped to 2500kbps and download down to 1800kbps. I had to reboot the router to get the speeds back up again, very frustrating.
I got BT broadband on 20/1/2010, set everything up and also fitted an I-plate. I noticed that line attenuation was 46db, this was previously 50.5 with sky and prior to I plate. The home hub sync was at 7200kbps at the start which i was very pleased with. I know this DLM thing is active for the first 10 days or so and speedtests during this time are not exactly accurate but still I was happy. after 3 days i did a speed test and got download of 5800kbps, chuffed to bits!
But, after 2 days at that speed the sync dropped to 2176kbps, gutted. I have only rebooted the router 3 times since the service started and each time the sync goes back to 7000kbps ish but drops again a day later. The thing I dont understand is the noise margin. Its currently at 24.5db, isnt that awfully high? Why is this? when I reboot it drops to 8-9db ish but then goes up again with the speed dropping.
currently connected to test socket, no other telephone equipment connected to any extensions
Can anyone please help/advise whats going on or how to rectify it? I'm wondering if theres a line fault somewhere.
And with attenuation at 46db I would have thought the speed could well be much higher than 2200kbps.
I'll stop babbling now,
Thanks

whitesp wrote:
Thanks for your reply Somerled,
ok so something is causing noise at a particular time, i had wondered about the quality of the home wiring, there are 4 extension sockets in the property, but again i am currently only connected to the test socket.
I dont have the old netgear router unfortunately so can't follow up on the suggestion you made.
God this is gonna be a nighmare to track down, although come to think of it I do have a dimmer on quite close to where the master socket is.
Can we say for sure that there definitely IS a source of noise/interference??
Many thanks
SOMETHING is forcing a resync, and at a low speed. The only thing that would cause that is a prolonged burst of noise.This is known to BT technicians as "REIN" (Repetitive Electrical Impulsive Noise). No point trying to get BT to investigate at this stage though, as it sounds very intermittent.
The way to spot radio interference noise is to use a suitable receiver - and the most convenient is a portable medium wave transistor radio. Tune to a quiet spot at the lowest end of the scale, and turn up the volume. All you'll hear is white noise and the occasional quiet crackle. A burst of noise strong enough to affect the DSL signal will be unmistakeable - a LOUD crackling/buzzing/rasping noise. If that coincides with a resync, you've found it. You then have to figure out what electrical device caused the noise.....
Another possible source of DSL noise problems is less obvious - noise caused by a line fault. This causes an unwanted mixing of the phone and DSL signal in a way that can't be corrected by the filters. This will have much the same effect as external interference noise.
Check this : does the router resync when the phone rings, or when the phone is in use ? If it does, then we're on to something - a fault known as an "HR" (High Resistance). If that doesn't happen, then we are back to external radio interference as the cause.
I suppose the HV lines you mention might have some effect, but it's a bit of a long shot. I'd expect noise from them would be a bit more constant, and would cause problems all the time, rather than intermittently.

Resetting the Noise Margin after Upgrade to 21CN

Hello,
A few weeks ago I requested the Noise Margin resetting when I was on ADSL Max - which worked a treat However, since then I've been upgraded to 21CN (see below) and the Noise Margin has jumped back up to an average of about 9db. The line has been 100% stable, but the Download speed has dropped slightly (although the Upload is a nice 1mb! ).
Please can someone post a link so I can contact the Mods again?
Thanks.

Here's a copy of the Stats so far.
FAQ
Test1 comprises of two tests
1. Best Effort Test: -provides background information.
Download Speed
4618 Kbps
0 Kbps
7150 Kbps
Max Achievable Speed
Download speedachieved during the test was - 4618 Kbps
For your connection, the acceptable range of speeds is 2000-7150 Kbps.
Additional Information:
Your DSL Connection Rate :5888 Kbps(DOWN-STREAM), 1187 Kbps(UP-STREAM)
IP Profile for your line is - 5000 Kbps
2. Upstream Test: -provides background information.
Upload Speed
981 Kbps
0 Kbps
1187 Kbps
Max Achievable Speed
>Upload speed achieved during the test was - 981 Kbps
Additional Information:
Upstream Rate IP profile on your line is - 1187 Kbps

My noise margin was hard set, but it's not now.

Some of you will have seen me going on about low noise margins affecting download speeds recently, and that the way to fix it is to get BT to hard set the noise margin at 6dB to prevent the problem. I had to do this a while ago when I was first upgraded to 21CN, and it was fine for a while. Problem is it seems the issue has returned, so I guess it's no longer capped at 6dB any more. Just making this thread so that the moderators can try to deal with it directly, since it took 15 attempts to even get BT to do as I asked last time!
Solved!
Go to Solution.

Hi
I am sorry to see you are having problems with your BT Service
I suggest you contact the forum mods they should be able to get this problem sorted for you this is a link to them http://bt.custhelp.com/app/contact_email/c/4951
They normally reply by email or phone directly to you within 3 working days they will take personal ownership of your problem until resolved and will keep you informed of progress
They are a UK based BT specialist team who have a good record at getting problems solved
This is a customer to customer self help forum the only BT presence here are the forum moderators
If you want to say thanks for a helpful answer,please click on the Ratings star on the left-hand side If the reply answers your question then please mark as ’Mark as Accepted Solution’

Why does my noise margin start off at 6.3dB then d...

Basically every time my modem is reset, the noise margin is 6.3dB and then after that, each day it drops off another 0.1-0.3 until it gets to 5.4dB why is that ? Obviously The reason I ask is, if it gets too low it will reset my modem by itself won't it? Could the modem be the reason.

this is what i mean guys, i know that one of them is 5.9 and the others 5.8 but why is there so much of a difference
non interleaved- http://gyazo.com/40d6ce989f2e6aad93e2ac53d0391fb5
interleaved- http://gyazo.com/ed752dd4dd109e63c72aea0357209b68
these are also pretty close and look at the difference
interleaved- http://gyazo.com/ee5da83220e8fc541577eee19fee26a1
non interleaved- http://gyazo.com/986ee7fafc206a50d368afbeda9150b9
the bottom two are slightly different but why such a big gap?
why when none interleaved the max is a lot lower?
if my sync speed is lower then why does my noise margin not increase rather than decrease and not rise back up?

High Noise Margin - Inconsistent Speed

Hi,
I had an issue between a month and two months ago, involving poor broadband speeds. This was eventually resolved after a line issue was detected and connection speeds are now better. However, when checking the noise margin through my homehub, the downstream noise margin is still much higher than before the fault (from reading other forum posts, I gather it should be around 6dB, whereas it ranges from 15dB - 17dB).
Download speeds also fluctuate frequently since the fix. This is more noticeable when I am using a platform such as Steam to download a larger file. Before the line fault, download speed was constant, and normally around 1.1 Mbps. Now, however, it varies anywhere from 200 Kbps to 900 Kbps and never remains constant for more than 2 or 3 seconds.
I have pasted the connection status page from my homehub below. Although the connection time shows 2 days, this was due to a restart I performed to see if it affected the line performance. Before this, I had 19 days continuous connection. A speedtest from speedtester.bt.com shows 5.67 Mbps download, 0.84 upload and 28.63 ping. Again, this is not as good as before the first line issue occurred.
Line state:
Connected
Connection time:
2 days, 16:37:59
Downstream:
6,607 Kbps
Upstream:
1,195 Kbps
ADSL settings
VPI/VCI:
0/38
Type:
PPPoA
Modulation:
G.992.5 Annex A
Latency type:
Fast
Noise margin (Down/Up):
15.3 dB / 5.9 dB
Line attenuation (Down/Up):
36.5 dB / 21.3 dB
Output power (Down/Up):
0.0 dBm / 12.5 dBm
FEC Events (Down/Up):
0 / 0
CRC Events (Down/Up):
1276 / 183
Loss of Framing (Local/Remote):
0 / 0
Loss of Signal (Local/Remote):
0 / 0
Loss of Power (Local/Remote):
0 / 0
Loss of Link (Remote):
0
HEC Errors (Down/Up):
1526 / 113
Error Seconds (Local/Remote):
0 / 157
Is there any reason why these issues are still occurring?
Thanks,
Ben

Hi,
Thanks for the quick replies!
I have tried the quiet line test and there is no noise whatsoever on the line.
I have tried the test socket previously, but am currently trying it again. The downstream speed has risen slightly, but the noise margin remains unchanged. I have restarted the homehub twice since connecting to the test socket, and it has currently been connected to the test socket for around half an hour altogether (in between homehub restarts).
I have posted a screenshot from the BT speedtester in the next post.
Here are the connection details from the home hub:
Line state:
Connected
Connection time:
0 day, 00:07:36
Downstream:
7,703 Kbps
Upstream:
1,183 Kbps
ADSL settings
VPI/VCI:
0/38
Type:
PPPoA
Modulation:
G.992.5 Annex A
Latency type:
Fast
Noise margin (Down/Up):
15.1 dB / 6.1 dB
Line attenuation (Down/Up):
36.5 dB / 21.3 dB
Output power (Down/Up):
0.0 dBm / 12.4 dBm
FEC Events (Down/Up):
0 / 0
CRC Events (Down/Up):
6 / 0
Loss of Framing (Local/Remote):
0 / 0
Loss of Signal (Local/Remote):
0 / 0
Loss of Power (Local/Remote):
0 / 0
Loss of Link (Remote):
0
HEC Errors (Down/Up):
15 / 0
Error Seconds (Local/Remote):
0 / 0
Thanks,
Ben

Help with resetting DSLAM/boosting noise margin?

I hope that by posting here I may actually get some help on my issue.
Had my BT Infinity 2 installed last week after a missed appointment (contractor), and got some helpful Openreach guys in, first last Monday to install the phone line - all went well, one pair was missing somewhere but a second OR engineer managed to solve this, told me I had a clean line.
On Thursday the fibre guys turned up, bit of hassle getting the HH5 to sync over the Data Extension Cable but got there in the end - seems the phone guy had done all the work and the line was working fine, no CRC errors, not far from the cabinet, a clean line.
However, the online fibre checker originally told me (and still does) that my estimated speed is 60-79 downstream and 19-20 upstream.
I am syncing at around 58Mb/s down but only just below 12Mb/s up - the HH5 has trained at this and it had been in and out the socket a few times on the Monday and again on the Thursday (same speed whether plugged in at the master socket or at the end of the DEC, I know this cable makes no difference anyway) - the fibre guys told me I have to get in touch with my provider (BT) to perhaps have the DSLAM reset as the auto sensing equipment at the exchange might have reduced my speed having been switched on and off so many times.
I know that the checker is just an estimate but it didn't say between 10 and 20 Mb/s, it is quite clear about the estimate of 19-20Mb/s - this was a major factor in me leaving the local cable company as I was already getting 10Mb/s upstream with them anyway. In this respect I am thinking that the (just under) 12Mb/s seems quite low.
So after phoning the customer service line a couple of times and despite being told to disconnect the router from the "white box" - I assume they mean the old Openreach modem - and getting nowhere as I insisited I don't have that and only have the new HH5, I composed a precise email detailing all of the above, and what do I receive back? This pearl of wisdom from someone in "Digital Care"...
"Dear Sir,
This is in regards to your e-mail which you have sent regarding the issue you are facing with your e-mail. I tried to call you to help you regarding your issue but could not speak with you."
Oh dear, did they actually read and understand my query - I also mentioned in my email that I could be contacted on my mobile number (given in the email, and on record as my installation was being handled by a specialist team after the missed appointments) as I do not have a telephone attached to my landline at the moment, or by email.
Now I run my own small computer repair business and am a professionally trained I.T. Consultant so I am 100% certain there is no problem on my end, how on earth do I go about getting this looked at because I feel like I am going round in circles? I don't think I can face another screen reader in India telling me to unplug my "white box"....
The noise margin seems quite low, can this be boosted - I must be between 150m and 250m from the cabinet according to the fibre guys.
Here's the relevant data from this morning:
3. Firmware version:       Software version 4.7.5.1.83.8.173.1.6 (Type A) Last updated Unknown
4. Board version:              BT Hub 5A
5. VDSL uptime:                1 days, 02:37:11
6. Data rate:       11869 / 58115
7. Maximum data rate: 11807 / 57862
8. Noise margin:               6.0 / 6.1
9. Line attenuation:         0.0 / 20.9
10. Signal attenuation:   0.0 / 19.9
and just taken now:
3. Firmware version:   Software version 4.7.5.1.83.8.173.1.6 (Type A) Last updated Unknown
4. Board version:   BT Hub 5A
5. VDSL uptime:   1 days, 10:16:36
6. Data rate:   11869 / 58115
7. Maximum data rate:   11793 / 56714
8. Noise margin:   6.0 / 5.8
9. Line attenuation:   0.0 / 20.9
10. Signal attenuation:   0.0 / 19.9
Thanks in advance for any help!

Thanks for the quick reply.
Here's the info:
Featured ProductsDownstream Line Rate(Mbps)Upstream Line Rate(Mbps)Downstream Range(Mbps)Availability Date High Low High Low
FTTC Range A (Clean)
79.5
60
20
19.6
Available
FTTC Range B (Impacted)
70.9
43.8
20
13.9
Available
WBC ADSL 2+
Up to 7
4 to 12.5
Available
WBC ADSL 2+ Annex M
Up to 7
Up to 1
4 to 12.5
Available
ADSL Max
Up to 5.5
4.5 to 8
Available
WBC Fixed Rate
2
Available
Fixed Rate
2
Available
Other Offerings
Fibre Multicast
Available
Copper Multicast
Available
As you can see my upstream is lower than the "low" impacted figure, and I was told by both the phone and fibre Openreach engineers that my line is clean with no CRC errors.
I'm not a business user.

Zero Noise Margin

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