The most common problem of ADSL connections, especially on long lines, is a low SNR margin value. The SNR margin (or Noise margin) is the relative strength of the DSL Signal to Noise ratio.
In case that you have upgraded your ADSL connection to a higher bandwidth (for example from 2 Mbps to 8 Mbps), you might be experiencing frequent line drops (disconnects). Especially during the night-hours there is a higher probability of having a lower SNR margin.
Depending on your ADSL router’s brand/model, you might be able to tweak the advanced connection settings.
Here I am going to describe how this can be achieved on a Netgear DG834PN router. It could be working with similar Netgear models (Google is your friend!).
Please make sure that you follow the instructions carefully, and only change the settings that suit you.
The first step is to enable telnet connections to the router. Thus, start up your browser and paste the following URL:
http://192.168.0.1/setup.cgi?todo=debug
The IP address should match your router’s address, so please change it accordingly.
The web interface is going to ask you for the administrator username/password.
Upon entering the correct details, you will see the message “Debug Enable!”.
Now that the telnet option is enabled, you need to connect to the router.
For example on a Windows command prompt just type “telnet 192.168.0.1”. On Mac/Linux just use the Terminal.
If the telnet connection is successfully established, type the following command to increase your SNR margin:
adslctl configure –snr 150
The 150 value is the percentage of the original SNR value.
For example if your original SNR value was 6 dB, than the 150 percentage would mean that you prefer an SNR value of 9 dB.
Increasing your SNR value, is decreasing your connection’s download bandwidth as well. However it’s better to have a lower bandwidth, than having a connection which constantly drops.
If you would like to restore the setting, than simply type:
adslctl configure –snr 100
… or just reboot your router. It has to be mentioned that the debug options are vanished after a router restart.
My SNR margin aslo go down at the night and in day time,
it just fine, I’m using a D-Link router and can you please explain why SNR margin goes down only at night?
Thanks!!!
Tx
Why do you say SNR will go down at night?
I am not an expert on telephone lines, however judging from articles around the web, it could be due to night lights, lowered temperatures, or other factors that increase the noise levels, and thus lower the SNR levels.
Also, solar radiation.
The major reason is in the evenings, there is a tendency to switch on lot of electronic devices, lot of people are watching TV, fluorescent lamps are on, Street Lamps are on, You are cooking, using Microwaves, you just pollute the space much more and it shows greatly in reducing the SNR. Try out early in the morning, you would know the big jump in SNR
Sri,
you are right that in night, all the electrical appliance like fluorescent, fan, and other may induce noise to the ADSL line. I tested my ADSL line, switch on certain fluorescent light may reduce the SNR, turn it off, the SNR increase.
[…] Ah.. aku tak reti nak ulas. Boleh baca pasal SNR di sini dan sini. […]
most people connectin’ to internet at evening, many connection on the line reduce snr.
It’s been more than 2 years since I posted my first comment on this post, and now I have got a better connection, my SNR margin is like 255, I think it’s because I live in few meters away from the exchange. And I have a 16 mbps ADSL line, how ever now I have a new problem, which is, when a rain starts, my ADSL connection disconnects and connect again automatically. That mostly 1 time, it’s ok again even through the rain. It only disconnect only on start of a rain. This is kinda weird and I don’t know why….
It a connection issue, or may be the interconnect from provider to your house got expose to rain. Try to check where the phone line go in your house, it should be interconnect to connect the wire. Make sure it well connect and may be put something to cover it up will help.
not working. that first address give an 404 error
there is a custom firmware for netgear by dgteam (just google) that lets you set the SNR permanently even if you reboot the router.
[…] Tweaking SNR margin to make your ADSL connection more stable | Decoding… – The most common problem of ADSL connections, especially on long lines, is a low SNR margin value. Why do you say SNR will go down at night? […]
[…] Tweaking SNR margin to make your ADSL connection more stable | Decoding… – The most common problem of ADSL connections, especially on long lines, is a low SNR margin value. Why do you say SNR will go down at night? […]
[…] Tweaking SNR margin to make your ADSL connection more stable … – Jan 21, 2010 … The SNR margin (or Noise margin) is the relative strength of the DSL Signal to … most people connectin' to internet at evening, many connection on the … 2015 at 21:40 | Reply Adsl Down Oberrettenbach | Sip-Voip-Austria. […]
Hi everybody, please let me ask a question: when I issue the adslctl configure –snr X, does the connection drop down, the router starts renegotiating a connection and a new IP gets assigned by ISP? Or the IP remains the same? Thanks for reply.
Why is it that some people say a higher snr is good and some people say a low snr is good. My is 9 and my speed is terrible.Sometimes it’s over 4mbps and sometimes it goes down to less than one mbps. I am supposed to be getting 5 to 6. My modem says 5888kbps but I am not getting it. Anyone actually know why this is? 5 tech visits and 7 or 8 chats with a tech have not fixed the problem. Actiontec GT784WNV.