Help! Why has my connection gone from hero to zero?

Rik · Sep 05, 2009, 11:41:02

I can't argue with a word of that, Tac.

David · Sep 05, 2009, 12:17:31

Lets hope you are proved wrong and that things will improve

MisterW · Sep 05, 2009, 15:01:39

QuoteMaplin is another source of phone cable, iiec, it's called CW1038

All the right numbers there Rik

, but not quite in the right order

Think you'll find its CW1308.

Rik · Sep 05, 2009, 15:28:01

Hey, I was close.

Too much Morecambe and Wise in my youth.

David · Sep 05, 2009, 15:45:21

Andre Previn

Rik · Sep 05, 2009, 15:47:42

Exactly - classic sketch.

David · Sep 05, 2009, 16:23:32

Great minds

JohnH · Sep 05, 2009, 16:48:30

Quote from: badpianoplayer on Sep 05, 2009, 16:23:32
Great minds

David · Sep 05, 2009, 16:53:06

Rik · Sep 05, 2009, 16:53:53

My mind is great. It's the connections it makes with the world that let it down.

David · Sep 05, 2009, 16:56:17

I'm with that guy

JohnH · Sep 05, 2009, 23:05:25

David · Sep 05, 2009, 23:37:29

emvisi · Sep 16, 2009, 22:32:34

Time for an update...

Well I've been back online for almost a week now, thanks to stirling work by Miriam and Brian who eventually managed to beat BT into unbreaking my connection

So I'm all set up on the new ADSL2+ Home Plus Package. Initially I was getting download speeds of around 5.5Mbps but, thanks to my running a phone extension right next to a noisy mains spur I hadn't noticed before

this dropped to around 500kbps for a few days. I immediately discovered the problem and after shifting the phone extension, obtained a pretty consistent downstream NM of 14dB (Line Attenuation still 42dB) and the download speed has bumped up to around 2.5Mbps.

I've been keeping an eye on the NM and it's been very stable since the weekend. That is, until a couple of hours ago, when it bombed to almost zero! I went round turning off just about eveything in the house and disconnected the phones, all to no avail. Out came the MW radio, and the noise on the line where it enters the house was terrific! From an untuned hiss, I could place the radio next to the line and hear a station coming through -- I detuned to several different frequencies and got the same thing.

I have quite a long modem cable (5m - ADSL Nation) so I powered down the router, moved it closer to the socket and used the short, simple lead which came with the router. The line resynced to the same speed as before (around 3M down / 1M up), throughput is the same (around 2.5M down) and NM is now back up to a stable 14dB. The trouble is, I don't know whether it was the action of resyncing the modem which improved things, or whether the long modem cable was the problem -- it's been fine till now. I can still pick up the radio station where the phone line comes into the house, too.

Can anyone shed any light on what might have happened there?

By the way, I can't use the BT speedtester at the moment as it won't accept my phone number as valid. Is this usual? And -- dumb question I suspect -- how can I tell what my target Noise Margin is?

Steve · Sep 16, 2009, 22:51:13

Not sure about the loss of sync but surely your target noise margin could be a noisy 15db or a quiet 12db. From my own experience I tried very hard to get my adsl router next to the filtered master socket, the rest of the network runs via homeplugs and a gigabit switch

emvisi · Sep 17, 2009, 07:48:03

I had my router right next to the master socket for several years -- only moved it recently while trying to isolate it from noise, as it's right below the electricity consumer unit, with mains cables firing off in all directions around it. The master socket is in a really stupid place

Rik · Sep 17, 2009, 08:44:47

Quote from: emvisi on Sep 16, 2009, 22:32:34
I immediately discovered the problem and after shifting the phone extension, obtained a pretty consistent downstream NM of 14dB (Line Attenuation still 42dB) and the download speed has bumped up to around 2.5Mbps.

Check the NM immediately after a re-sync, that will tell you what the target is - there's no formal way of doing it, I'm afraid. I'd guess at 15db from what you say and your speed relative to attenuation.

QuoteI have quite a long modem cable (5m - ADSL Nation) so I powered down the router, moved it closer to the socket and used the short, simple lead which came with the router. The line resynced to the same speed as before (around 3M down / 1M up), throughput is the same (around 2.5M down) and NM is now back up to a stable 14dB. The trouble is, I don't know whether it was the action of resyncing the modem which improved things, or whether the long modem cable was the problem -- it's been fine till now. I can still pick up the radio station where the phone line comes into the house, too.

A shorter lead is always better, having the router next to the master is always going to give you the best result. The radio station is odd, is it always the same station, regardless of the radio's tuning?

emvisi · Sep 17, 2009, 09:31:48

Quote from: Rik on Sep 17, 2009, 08:44:47
Check the NM immediately after a re-sync, that will tell you what the target is - there's no formal way of doing it, I'm afraid. I'd guess at 15db from what you say and your speed relative to attenuation.

Ah, thanks. I'll check this next time. In fact I may stick the Netgear back on today so I can run router stats -- I'm less convinced it's faulty now since the line suddenly got really noisy last night using the other router.

Quote
A shorter lead is always better, having the router next to the master is always going to give you the best result. The radio station is odd, is it always the same station, regardless of the radio's tuning?

That would be my preference -- may need to look at moving the socket.

I didn't really pay attention to whether the radio station was the same, but I doubt that it was. I think the long phone lines were just providing the radio with a supplementary aerial. The phone line runs overhead to the house, so it probably picks up anything and everything!
However, RF comms wasn't my strongest subject, so I'll have another listen this evening to make sure.

Rik · Sep 17, 2009, 09:33:28

It might be worth having a word with support. If that's always present, BT might be willing to fit an RF filter.

emvisi · Sep 18, 2009, 12:04:00

Checked it again last night. The phone line was just providing the radio with an enhanced aerial. The MW frequencies do get very busy in the evenings down here. Doesn't help that we're located right on the English Channel.

Anyway, I finally managed to do a BT speed check last night and discovered my profile was an underwhelming 2500 kbps. However, the line went doolally again this morning: noise margin dropped down to between 0 and 3 dB, modem resynced at just over 1000 kbps. The BT speedtester again refused to work for me. I waited till things settled down, rebooted the router and synced at just over 3000 kbps again, but throughput is now below 1000. Noise margin was initially 19dB; now reading 16dB a couple of hours later.

I realise that I might still be on the training cycle at the moment, since my line was switched to ADSL2+ just over a week ago, but I'm fast losing confidence that I'm ever going to obtain a stable ADSL connection. I've been round and round making sure that everything in the house is as good as it can be, to the point that I've replaced the master socket faceplate with a new one from ADSL Nation, removed the master socket from the wall so it's lying on the floor away from any passing mains, the modem/router is a couple of feet away, on the stairs - away from all noise sources but as close as possible to the router, and there's only one corded phone plugged into the faceplate, with another filter in line for good measure. It can't stay like this, but if I can't get a reliable connection when I've gone to these lengths....

Rik · Sep 18, 2009, 12:09:55

I do sense that you need an RF filter on your line. Your throughput will have been hit by the 1k resync, which will have dropped your profile, and it also looks like you've now got a target noise margin of 15db. Have a word with support about the RF problem.

emvisi · Sep 18, 2009, 12:23:43

Will do. Thanks again, Rik.

emvisi · Sep 18, 2009, 12:43:49

Brian on the case, starting with BT line check...

Rik · Sep 18, 2009, 12:45:39

emvisi · Sep 21, 2009, 12:53:25

Still waiting to hear back from IDNet/BT...

Anyway, just used the (corded) phone on the BT line and noticed the ADSL noise margin dropped to 1dB at the same time. Recovered to 12/13dB when the phone was put down. I tested again (phoned the BT line from the Virgin Media one) and it seems to be repeatable. My wife, on the BT line, said she could hear some occasional crackle.

Modem and phone are both connected straight into the brand new ADSL Nation faceplate; modem on 1m cable, phone via 3m extension and a second filter for good measure.

Could there be some cross-talk problem upstream?