Reducing Noise

I have finally had BT turn interleaving off. I can sync upto 7.5Mb during the day, but at night i'm struggling to get the minimum sync for 5Mb BRAS.

I've moved the router (585v6) downstairs to the master socket that has a XTE-2005 face plate filter on it. My router was previously upstairs on an hardwired external extension behind my LCD tv and Xbox 306 which I felt was probably adding noise.

Problem is, a laptop & computer are very close to the router at the master socket.

Will this also add noise? It seems at about 2-3am my router disconnects and re-syncs after hanging on at 1db. So basically I need to find 2-3 db more SNR.

Any ideas?

Are you saying that your SNR margin is getting down to 1dB? What do you get at the master socket? Sounds like you need to find a bit more than 2-3 dB ideally!

Have you got any other extensions? How about any joins? I got an extra 15dB margin (on a fixed adsl service) by hard wiring into a junction box where I had an extension plugged into an extension.

AL.

I have a face plate filter and the extension the router is on is directly hardwired into the broadband side of the face plate filter.

If it's really that close, then a few things that might just help are:

• keeping anything electrical (including mains cabling) as far away as possible from anything carrying the ADSL signal (router, router phone cable, master socket, BT line cable);
• double filtering the extension wiring (ie: adding an additional filter between extension wiring and the back of the XTE-2005 face plate);
• using a mains conditioner on the router power supply.
  

Having said that though, surely it's easier just to raise the SNR margin by a couple of dB? If keeping the line up is that important, isn't it worth trading a few 100kbps sync speed for it? You're probably getting so many dropped packets at the moment that the extra sync speed is wasted anyway.

I understand the extension is wired into the master socket face plate, but if you remove the face plate and plug the router directly into the socket behind it (thus taking the extension wiring out of the equation) what noise margin & sync speed do you get then? If it's not much better then the noise problems are coming somewhere in the local loop from the exchange - speak to BT! Otherwise, if there is a difference, check the quality of the extension wiring or the connection into the extension (the master socket is obviously new, but is the extension socket ok - eg corroded terminals?)

The recommendations from cahaddras were all good, but regarding raising the noise ratio, I believe this refers to the target noise ratio at which to set the sync speed, and I think this requires a special download tool, like DMT, to change settings on the router - right? Otherwise it is handled automatically with a target between 3-15dB but usually around 6dB.

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I think this requires a special download tool, like DMT, to change settings on the router - right?

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That's the most flexible way. An alternative would simply be choosing when to resync the router. If the target margin on the line is (say) 6dB and you resync when the current margin is 4dB, then the margin should go up by 2dB.

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If keeping the line up is that important, isn't it worth trading a few 100kbps sync speed for it?

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If stability is more important than speed, then turning interleaving off was not a wise move either (unless he's an avid online gamer).

http://img295.imageshack.us/img295/3079/testsocklo8.png <------ Thats from the test socket. I know the margin is low but i'm just curious about how low it can stay stable.

http://img224.imageshack.us/my.php?image=extensioniy1.jpg <-------- The Extension

Can you see any problems in the graphs at all?

Thanks

Edited by wolvesmad (Thu 01-Mar-07 10:57:31)

On those graphs using that program, are you actually able to reduce your own noise margin manually?

Yes. I manually reduced it to 2db out of curiosity. It's running at 9.5db at 5668kbps. I think it's crazy how I manage to lose near enough 10db SNR as the router will re-connect from 5.6Mb down to 5.2Mb at about 8pm.

I thought the noise margin was all to do with your internal wiring, filters etc. I didn't think you could control the noise margin your self. So decreasing this to a 'stable' rate will increase your sync rate?

sorry to hijack your thread mate, just a few questions.

If I'm able to manually lower my Noise margin, will this increase my sync speed? it current sits at 12db (downstream) and syncs at 3.2megs.

If i keep decreasing the margin by 2db, as soo as i starts to drop and reconnect i guess ive found my stable rate.

What is the advantages of such a tool?

thanks

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What is the advantages of such a tool?

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It allows you to override the target margin set by the ISP (or by Mad Max if you're stuck with an ADSL Max service), allowing you to experiment with trading off sync speed against stability.

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I know the margin is low but i'm just curious about how low it can stay stable.

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As I said, stability is one thing, but you seem to be ignoring the error rate. The stats are showing 124 errored seconds out of 240. There's no point in a high sync if up to half the data packets transferred are dropped with errors.

is there a guide on this DMT?

first off, i don't understand why you guys are so anti-interleaving. my line is interleaved, i have been able to connect at 8128kbps (not generally anymore, but read on and you'll know why) and my latency is sub 35ms on a UK server which isn't exactly poor.

i had issues with low SNR. thought it was a problem at the exchange. this is what i did, call up your ISP, get them to give you a log of times when you have lost connection (as in lost sync) and ask them HOW your connection dropped. they have info on it, since Demon told me. the causes i was having was due to my router giving port errors left right and centre.

i had a linksys WAG354G which was giving me all sorts of issues. i replaced it with a netgear DG834N. my new router gave me a +5dB improvement in SNR! my sync speed has dropped a bit to around 7500. but my connection is stable and the latency is still perfectly fine.

Edited by EonX (Thu 01-Mar-07 22:10:49)

Interleaving destroys online gaming. My ping with it on was 45ms to jolt. Ping with it off is now 16ms.

I had the 834PN, superb for wireless, great on fixed service..........pure pants on Max.

I was sync'ing at just under 4Mb on the netgear, just over five on the ST585v6.

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is there a guide on this DMT?

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I've never seen a guide. The web site is http://dmt.mhilfe.de/, although mostly in German. However use of the tool is regularly discussed in ThinkBroadband forums, here for example.

I'm finding that i'm getting thousands of CRC error even when my SNR is 6db.

I've had 17596 CRC's in 19 hours of uptime =(

That'll be why you had interleaving switched on. Actually that's probably borderline as far as significantly affecting speeds. I'm not a gamer so I'm not sure what effect a dropped packet from time to time would have on this. You might experiment with the options I suggested to reduce these errors.

Could this not be the router casuing all these CRC's?

(Speedtouch 585v6) running on 6.1.4.3