Increase in SNR = drop in sync

punto123

Hi all

For the last six month my sync has been 4282kbps with an snr at 6db and ip profile of 3500

Last night i checked my sync was 2848Kbps with the snr around 14 - 15 db and ip profile of 2500

i re synced my router this morning an here are my stats as of now


ADSL Link Downstream Upstream
Connection Speed 3904 kbps 448 kbps
Line Attenuation 39 db 10.5 db
Noise Margin 13 db 23 db

how can i get the snr down for the sync to increase, what could have caused the sudden increase in snr?

is it worth having the snr reset ?

spoke to my isp tech support they say bt could be doing some work at the exchange which could cause the high sync, is that right ?

I am always into the test socket using a netgear dg834g

kwikbreaks

Noise has caused the connection to drop out a few times and the dynamic line management routines have increase your target margin in an attempt to maintain stability.

BT IPstream DLM sucks and is another good reason to swap to LLU if possible.

If your connection remains stable the DLM is supposed to reduce th target again but it is a very slow process - at least a couple of weeks to recover to a 9dB target from what I'm guessing is 12dB then another two to get back to 6dB. If a sparrow farts near the phoneline during that period all bets are off. It really is that dire.

Some routers can be tweaked to override the default - http://dmt.mhilfe.de/ - http://www.kitz.co.uk/routers/DMTv7.htm

It's unlikely that you'll be able to get a manual reset.

punto123

no llu in my area , the post office say they will reset my snr of i want , so maybe take this option

can my netgear dg834g v3 be tweaked

punto123

My snr has gone back down

here are my stats as of now,

ADSL Link Downstream Upstream
Connection Speed 3904 kbps 448 kbps
Line Attenuation 39 db 10.5 db
Noise Margin 4 db 23 db

How come my snr has gone down so quick?

if i re boot the router in the morning will i get a higher sync now my snr has gone down ?

or should i just leave it to go back up on its own?

many thanks

many thanks

aerostar

The more times you reboot your router, the more times the exchange will think your modem is having problems, and so reduce your speeds. If you want to reboot, then switch off the modem when you go to bed and switch it on in the morning, that way the exchange will not take it as a modem problem.

kwikbreaks

punto123 wrote: »

My snr has gone back down

here are my stats as of now,

ADSL Link Downstream Upstream
Connection Speed 3904 kbps 448 kbps
Line Attenuation 39 db 10.5 db
Noise Margin 4 db 23 db

The SNR has gone down because noise has increased. Your target will still be 12dB as you will see if you resync it. I know you haven't done so because it is still running at exactly the same sync as your earlier post.

The DG834v3 used a TI chipset and in my own experience (but to be fair not everybodies) is a terrible piece of kit that causes problems just like you are seeing with a fluctuating SNR.

woody01

Is this SKY?
If so, they are running DLM, and are stiffling your connection.

punto123

kwikbreaks wrote: »

The DG834v3 used a TI chipset and in my own experience (but to be fair not everybodies) is a terrible piece of kit that causes problems just like you are seeing with a fluctuating SNR.

many thanks for everyones help , what router would you suggest , i do alot of xbox gaming so need one whee the nat port is open.

i am confused i always thought if the snr went down the noise decreased and if the snr went up the noise increased , obviously i am missing something here

no i am not with sky i am with the post office many thanks

kwikbreaks

SNR stands for signal to noise ratio. That means it is signal divided by noise and that number will go down if the noise increases. In general ADSL routers report a margin rather than the actual ratio but it amounts to pretty much the same thing.

Ideally you want your connection to remain fairly stable on ~ 6dB of noise margin. There will inevitably be some reduction in margin (increase in actual noise) in the evenings and overnight because AM radio signal levels increase and there is generally more stuff getting switchd on and off in houses nearby.

Regarding routers - I always rated the SpeedTouch 585v6 which is no longer made so it would be an eBay purchase. Later versions of the DG834 or the DG834GT are good too. Most routers that use a Broadcom chipset are fine (check with google) but the TI AR7 chipset in my own experience isn't.