Low SNR, whats causing it?

WotDa · 13 Mar 2007 at 20:05

Hi,

I know its night, and as such SNR drops anyway, on my old router it would drop from about 10-14 to 5-7. This would cause loads of disconnects, and plenty of errors aswell.

However, my new router, Linksys WAG200G, drops the SNR from 10 during the day to anywhere between 0 and 6. The weird thing is, it hasn't dropped connection, at all. Although I assume the errors are still in the thousands.

Now then, the other day with my old router I fixed the wiring in the house, this increased my SNR slightly but not enough to stop the disconnects at night, so I went to disconnet the extension wiring, checked the SNR, and it had dropped, connected it back in and it went back up.

So, what else could cause this?

Whilst i'm here, how do I find out the uptime of my DSL connection and router? I've searching Google, and in the web interface but can't find it anywhere. :confused:

Thanks in advance.

*FLASH* · 13 Mar 2007 at 20:45

Your screen shot is showing 0dB surely that cannot be correct? That would indicate severe line issues. The 27dB downstream indicates your probably as close as a mile away from the exchange hence why your getting the full 8Mb ADSL Max speeds.

Make sure there are no electronic devices intefering with your router. Also make sure there no thermostats etc... close by.

Could also be a filtering issue have you checked the filters/master socket?

tolien · 13 Mar 2007 at 21:12

As suggested, try the master socket with no extensions or phones, or the test socket, without filters and just a short bit of extension cable and see what you get.

NachT · 13 Mar 2007 at 21:21

I'm having the same problem WotDa. But not as bad as you ;P

My SNR can drop to 2db at the lowest, usually 4 - 8db during the day and night. I've also tried the master socket etc but I got the same results.

I get around 1,200 errors a day because of the low noise. You can contact your ISP and get 3db added on, but you'll loose 1/2 meg sync. I think i'm going to have to get about 6db, only loose 1mb

*FLASH* · 13 Mar 2007 at 21:47

NachT said:
I'm having the same problem WotDa. But not as bad as you ;P

My SNR can drop to 2db at the lowest, usually 4 - 8db during the day and night. I've also tried the master socket etc but I got the same results.

I get around 1,200 errors a day because of the low noise. You can contact your ISP and get 3db added on, but you'll loose 1/2 meg sync. I think i'm going to have to get about 6db, only loose 1mb

There are certain routers out there were you can alter your target SnR yourself using a created gizmo.

WotDa · 13 Mar 2007 at 21:58

Thanks, just went and tried with no phones and it was the same, I would try the test socket but there isn't one and it is currently in the master socket at the moment.

Flash, yes it does say 0db, and thats the very reason I took the screenshot. The router may be mis-reporting it, because I personally don't believe it could hang on to a connection with it that low. The only electrical thing near the socket, is the router, about 1 1/2 foot away.

tolien, not sure what you mean without filters and just a short extension. :confused:

NacthT, I increased my SNR on my old Speedtouch router by 3 and I kept the same sync.

And I was going to contact UKFSN first about getting it increased, but I though I had best check to see if I can do anything about it first.

tolien · 13 Mar 2007 at 22:04

WotDa said:
tolien, not sure what you mean without filters and just a short extension.

What it says on the tin. Use a short bit of cable to connect your router to the test socket, and don't use any filters.

Kerazee · 13 Mar 2007 at 22:08

dunno if it is something to do with linksys routers but my WAG354G can show a drop in SNR to 0 without any disconnects, in actual fact it is sat here now fluctuating between 1 and 3 with no disconnects

WotDa · 13 Mar 2007 at 22:12

tolien said:
What it says on the tin. Use a short bit of cable to connect your router to the test socket, and don't use any filters.

Aha, so a test socket would be handy for that option then?

When were the test sockets forst introduced? This house is only about 35 years old and I expected it to have one, but it doesn't. :/

NachT · 13 Mar 2007 at 22:41

Your SNR can actually drop below 0db, it's not misreading it.

Some routers can hold onto connections beter than others, I read somwere that the netgear 834G's can hold onto connections evan if the noise drops below 0db :eek:

I'll try and find the page were i read it.

Although, evan tho you can still hold the connection at extremely low SNR's, you'll probably start to get packet loss / errors / etc.

EDIT: This might be of use http://www.kitz.co.uk/adsl/lowSNR.htm

WotDa · 13 Mar 2007 at 22:47

NachT said:
Although, evan tho you can still hold the connection at extremely low SNR's, you'll probably start to get packet loss / errors / etc.

Thanks for the link will have a browse.

Re the errors, I can tell they're there, especially when downloading, but I can't see how many I've had.

Edit: Might it be worth getting onto BT about a possible fault with the line?

NachT · 13 Mar 2007 at 23:02

WotDa said:
Edit: Might it be worth getting onto BT about a possible fault with the line?

I'm in the same position as you mate, have thousands of errors, loades of packet loss, and my upstream... well, I can't realy call it an upstream lol.

I've contacted Enta about it 6 times, and they've contacted BT. Yet nothing has been fixed yet, so they're sending a BT engineer to my house :rolleyes:

It could be your line.

A friend of mine connects to the same exchange, and he's sync'ed at 8 meg ( the same as me ) he also has the same SNR as me, yet his line is fine. He uses a different ISP to me tho. Enta are realy good, so it cant be them at fault.

In my case, i think it's my line. Line tests done by BT and enta on my line come back clean, for some reason.

WotDa · 13 Mar 2007 at 23:08

NachT said:
In my case, i think it's my line. Line tests done by BT and enta on my line come back clean, for some reason.

Looks like an excuse for me to send an email to Enta instead of Jason tomorrow then.

I'm just worried that if they find out about it they'll whack interleaving on.

NachT · 13 Mar 2007 at 23:15

I've got interleaving off on my line, if you don't want it on you dont have to have it on.

I dont know if they'd rather you have it on, it would help with the errors... but it would reduce your ping. I never used to have problems up untill 2 months ago, I guess somthing must have happend to my line around that time, not to sure.

You could try adding an extra 6db to your SNR and see what it's like for a week, if it's still bad you could turn interleaving on for a week and try that.

WotDa · 13 Mar 2007 at 23:19

I'll do a few rounds of emailing tomorrow then. Thanks.

Interestingly, I've never, ever had interleaving on, AOL must have felt the need to switch me to fast path/leave me on it, and Enta just left it as it was.

Although, saying that, AOL might have swapped it when I complained about being routed via New York, 200-300+ ping on my own clans server wasn't fun when the auto kick was set to 250..

NachT · 13 Mar 2007 at 23:20

I've never actually had it on either

So I couldn't tell you if it makes much of a difference in preformance or not.

tolien · 13 Mar 2007 at 23:39

Interleaving defaults to automatic, in that it's off but but will switch on if you start showing a lot of disconnections.

WotDa said:
Aha, so a test socket would be handy for that option then?

I did say master or test sockets

The outside socket and the test socket are more or less interchangeable, as long as you have no hardwired extensions. The test socket just disconnects any extensions you have...

When were the test sockets forst introduced? This house is only about 35 years old and I expected it to have one, but it doesn't. :/

Master socket here is ~20 years old and is the one part version (ie doesn't have a test socket). I've been getting round to paying BT to replace it for >a year now...