Improving DS Margin.

My current line stats:
DS Margin 15 (fluctuates)
US Margin 24
DS Line Attenuation 30
US Line Attenuation 31

The DS Margin is a concern because it has always fluctuated rapily between 10 & 15. Around 10pm at night it sometimes dips to 8. I'm wondering if it's possible to stabilise that.

The router is plugged directly into the internal socket of a BT NTE5 master socket. I removed the faceplate a while back and have just ordered an XTE-2005 from ADSLNation to see if it does better than the cheap (Demon issued) microfilters I'm using. Having said that, the Demon filters improved the US Margin by 4db over the Pipex issued one.

There are NO extension sockets around the house. Had them all removed when I installed DECT phones many years ago. All redundant cabling was removed also.

About 12 inches of thick brown cable (fitted by BT approx. fifteen years ago) goes between the master socket and the junction box (they're literally on opposite sides of the same wall).

**Is such old cabling likely to be a problem?

I looked inside the junction box and it's a tangled mess in there. (Normal?) Also, there are a set of cables in there for a second telephone line that was disconnected around ten years ago. Those wires no longer enter the property and have been cut at the ends. They form part of the tangled mess.

**Could those redundant wires be causing any problems?

Thanks for any help.

I'll prepare you for the bad news - the faceplate filter is unlikely to make things any better. The good news is that it probably won't make them worse. Your DS margin seems a little high, but that might be because of the noise fluctuation. Unfortunately some lines seem to be worse than others for noise, and by removing all your extension wiring, I think you've done about as much as you can do. Things may get a little bit better as summer approaches and the days get longer, because (as you've already noted) the noise increases during hours of darkness.

Edited by deleted (Mon 05-Feb-07 17:12:42)

It's unlikely that an XTE-2005 will have much effect as you have no extensions, though, on the other hand, the ADSLnation filter is likely to be superior to the Demon-supplied ones, so you may notice some improvement.

I notice that you're on Max, in which case your margins are not bad. Do you sync at full rate? Dropping to 10dB or even 8 at night is perfectly acceptable. I wouldn't worry.

Good point. I forgot to ask if he was sync'd at full rate

Well, I was only guessing, but with margins of those on Max, I'd be surprised if they weren't!

The US and DS attenuations look a little suspicious though - one is usually much lower than the other, and he has 30 and 31.

True, but they're not poor at all so not worth worrying about.

Sorry. Forgot to mention that my sync rate was 8128/448 without fail for two months. But then I upgraded the firmware on my Addon GWAR3000 with routertech version 2.1 last Friday and a few hours later, the DS sync rate dropped to sub 7000 speeds. Often dipping to 5.5 and 5.6 over the weekend. This was a big shock given what I'm accustomed to.

I'm not certain the sync rate drop is due to the fw upgrade, but I'm unable to roll back to the previous version and it does seem a little suspicious. I also plugged in the Demon provided Alcatel Speedtouch modem for the first time to see what that synced at and it was always 5.6 downstream :O Wish I'd tried it out back in December or January now to see if synced at 8128/448 like my router was doing at the time.

Well, it will be woth the 12 quid for a tidier socket provided the DS noise and US/DS attenuation isn't made worse. So the constant fluctuation isn't so much a problem then? It changes constantly, sometimes jumping between 8 and 15 several times in a few seconds (at its very worst).

Edited by dneb (Mon 05-Feb-07 17:55:54)

So with the stats that you posted originally, are you saying you're only achieving a ~6Mb sync?

Since last Friday, yes. This is what they look like right now:

Connection Status Connected
Ds Rate (Kbps) 6464
Us Rate (Kbps) 448
DS Margin 12
US Margin 24
DS Line Attenuation 30
US Line Attenuation 31

Just refreshed a few times and DS Margin is fluctuating between 10 & 12.

Strange. There's certainly the potential there for more, but I couldn't say what's caused the drop in sync.

Aye. I just connected with the SpeedTouch 330 to see what that says about line attenuation and noise margins, and it's the same as the GWAR3000 stats I posted except for a 1db increase in DS attenuation. It also syncs at an even lower rate:

ReceiveAttenuation_dB= 31
SendAttenuation_dB= 31
ReceiveMargin_dB= 15
SendMargin_dB= 25
RxOutputPower_dBm= 0
TxOutputPower_dBm= 0
Layer1DownstreamMaxBitRate= 5664000
Layer1UpstreamMaxBitRate= 448000

Edited by dneb (Mon 05-Feb-07 20:52:25)

Make sure you're running the drivers for 8Mb lines.

http://www.speedtouch.co.uk/downloads/330/301/PPPoA_0-38_ISO_MODE.zip

You may well be running the the standard Windows driver package from SpeedTouch. Try this and if your sync improves, we know the router is to blame.

I did select the >4Mbps driver option from the CD, but gave this one a try anyway and my sync rate changed to 6.1 Mbps. Consistently too. This is what the router is syncing at lately around 10pm at night (it is 10:12pm right now). Previously the modem would sync at anything above 5.7 Mbps, whatever the time of day or night.

Modem stats are all the same except for:

Layer1DownstreamMaxBitRate= 6176000
Layer1UpstreamMaxBitRate= 448000

I wish I could find the original firmware for the Addon GWAR3000 so I could rollback the router and see if it syncs at 8128/448 again, but the manufacturer doesn't make it available. I thought I'd backed it up before reflashing, but I later discovered the bin file was useless (loaded with nothing but null bytes). :/

Okay, so it looks like the SpeedTouch issue was the drivers, and you're now getting the same performance from both devices. It really is bizarre because you're by no means using the full potential of your line. I think it might be a good idea to get in touch with your ISP if it is a problem for you. I can understand your frustration as you once had the highest possible sync rate, but what you're achieving now is still excellent.

Thanks a lot for the help and clarification Sebastian. I'll give them a call. =)

I don't mean to be negative, but don't get your hopes up. A family member of mine had downstream sync of less than the upload, millions of HEC and CRC errors, and an extremely unusable connection. Even after a BT engineer visited, it was apparently operating within the guidelines!

Well the XTE-2005 just arrived, and although the US Margin and Attenuation stats are the same, the DS Margin fluctuation is nowhere near as severe. Previously, it would move rapidly betwen 10 & 15 (dipping lower at night), now it's moving between 13 & 15 at a much slower rate. I switched back to the microfilters and the fluctuation got worse, so there's a definite improvement with the XTE-2005. I'm not certain a more stable DS Margin is something to shout about. Indeed, I'm still syncing at between 5.6 & 6.6...so I'm still scratching my head in that regard.

Also, Demon Tech support couldn't care less. Oh well. It's not like it wasn't expected.