SNR Margin reset

Living at the end of a fairly long line (4.03m as the crow flies) I was happy to achieve a stable 2 meg connection. However about 2 weeks ago, we experienced a series of power fluctuations which caused my router to re-sync very quickly several times in succession. I believe this triggered BT's DLM to cut in as my noise margin suddenly shot up to 12 db and my sync speed dropped to 1500 kbps.

After a week, my noise margin has dropped to a 9 db and my sync has been stable at 2016 kbps for the last 7 days.

The question is, will the SNR eventually drop to the default 6 db and allow me to achieve 2 meg again or am I stuck on 9 db for ever ?

Router stats at present are ;

2016/448
63.5/31.5
9.4/15.0

Thanks

Ron

It should drop to the default 6dB after a couple of weeks of stability.

Thanks John2007, that's what I was hoping but as it went down from 12 db to 9 db fairly quickly, I was a bit concerned that it might have got 'stuck'.

Cheers

Ron

In reply to:

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It should drop to the default 6dB after a couple of weeks of stability

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If you're on a poor line, 2 weeks of absolute stability is surprisingly hard to achieve.... :-)

In which case you would need the extra stability given by an increase of target SNR margin.

In that case you've 2 other possible courses of action (maybe)...

If available on your exchange switch ISP to either Be/O2 or UKOnline who don't use DLM (apparently Sky are introducing it so possibly UKO may follow as they are both EasyNet). Some other LLU providers don't use DLM either but they have extremely bad reputations.

Buy a router which allows you to override the default noise margin set by DLM using the DMT software

http://translate.google.com/translate?hl=en&sl=de&u=http://dmt.mhilfe.de/

or CLI if you know the correct commands. Speedtouch 585v6 on 6.1.4.3 firmware is probably best bet here as it holds the tweak across power cycling which some others don't.

Kwikbreaks wrote:
"Speedtouch 585v6 on 6.1.4.3 firmware is probably best bet here as it holds the tweak across power cycling which some others don't."

I suggest treading carefully with the newer Speedtouch boxes. I have just rejected a 546 v6 (the non wireless version) that came with firmware 6.2.17.5 installed. That would not work with DMT and appears to be not tweakable, although I didn't investigate for too long. It appears that Thomson have restricted adjustment capabilities with the newer firmware. See also comments in the DMT forum (eg. at http://forum.mhilfe.de/viewtopic.php?t=4091 ) which seem to confirm these restrictions. I described my problem in http://forum.kitz.co.uk/index.php?topic=2378.0 and received various feedback.
I was not prepared to start life with a brand new box by changing the firmware to an older version and finding that I was cut off future updates by being stuck on a dead-end.
When my return is processed, I will look at the Netgear DG834 v4 (I want a wired box only, not wireless); I understand it has similar tweak capabilities.

Correct - the 6.2... firmwares don't support tweaking which is why I specified the 6.1.4.3 firmware which is the latest that does support it.

When I was using a 585 there were no problems swapping between 6.1.4.3 and the 6.2... firmwares but I suppose that may have changed.

I think the 585v6 has been superceded now so you'd need to find one on eBay where they appear regularly as they used to be dished out by some ISPs and people have bought others with faster wireless (probably a big mistake as the 585 has one of the very best ADSL modems available).

I am not suggesting there are necessarily any problems in going back to the earlier version.
My point is when buying a new modem with a newer chip and looking for better performance and a steady upgrade improvement path, it is not encouraging to see that the first thing one has to do is to go back to the earlier firmware.
Do I want to depend on a modem where the manufacturer has decided not to allow the tweaks in the future? No I don't - not if I can use an alternative that continues to support such options. I want to be able to use upgrades as they come along.

Ok, I've downloaded the DMT tool and set up up to work with my router (Netgear DG834G V4) but before I go ahead and tweak the SNR margin, are there do not do's to be aware of ?

And if I set the default margin back to 6 db, will this be retained after a router re-boot ?

Thanks

Ron

but before I go ahead and tweak the SNR margin, are there do not do's to be aware of ?

Yes.
Don't take it down below 3dB, especially if you're doing it during daylight hours.

And if I set the default margin back to 6 db, will this be retained after a router re-boot ?

Not unless you can find a "saveall" command, or similar ("saveall" is a telnet command used by the Speedtouch routers - same ADSL chipset family, but it may not be available on the Netgear - it certainly isn't on the Belkin 7633 ).

Ok, thanks for that.

I'll take it down to 6 db and leave it at that.

Cheers

Ron

In reply to:

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If you're on a poor line, 2 weeks of absolute stability is surprisingly hard to achieve.... :-)

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No it isn't, just turn the router off each night when you go to bed. You do not have to maintain a constant connection for 14 days solid, you can turn it on and off again at will (although on and off like a loony wont help you) and so long as you hit around the same sync every time you are on a winner. Turning it off at night means there is little chance of the router rebooting at a lower sync.

With lots of things newer can mean better but not always. The only thing you can guarantee about newer is that it cost the manufacturer less to produce.