Low quality wiring & electrical interference

Hi all,

I have established that I have a problem with a loss of sync when one particular computer is switched on. I'm sure the probelm is an electrical interference issue as the computer does not need to be connected to the router, 100% of the time if the PC is switched on sync drops from 2400kbps to 1600kbps. Once the problem PC is switched off the router can be reset & the sync comes back to the higher rate. I managed to test a 2nd PC while the household was empty & the sync rate stayed at 2900kbps for 1 week without dropping out at all (I checked the router log). As soon as the family return the sync drops a little lower to 2400kbps - I assume due to more electrical appliances being used, however I can't find any other specific appliances that cause a sync reduction.

This is my mothers house, built 20 years ago & all the wiring is pretty shoddy. There are a number of phone line extensions which I've tried disconnecting where possible, but it doesn't help. Trouble is I don't think I can completely bypass the extensions & use the master box, see photos below: there is a box with no socket on the opposite side of the wall where the BT grey box is connected to the outside, this is wired to a 2nd box in a spare room which I thought was the master (apparently not) Click the links below for images (90K in total full size)

Photo 1: BT grey box outside wall
Photo 2: BT master box but no socket?
Photo 3: BT 'master' socket on extension?

My feeling is that it would be best to strip out all the current wiring & install a new NTE5 with built in filters & interstitial plate, then add any extensions off that. However I'm worried that BT could charge ���s & might not solve the problem.

Do any of the experts think we would be entitled to the:

"Conversion of hard-wired master socket to Linebox and Regularisation of illicit master socket"

This might be ideal - as mentioned this is for my mother & she is entitled to a disabled person blue badge, so the charge for the above might only be �30 rather than the �140 that seems to be the standard minimum for a call out these days.

Thanks for any help or advice

Edited by deleted (Tue 03-Jun-08 01:48:15)

Photo 2 - can't you fit a filtered ADSL face-plate in place of the socket-less front plate, and connect your router there?

Photo 3 - are you sure it's a master socket? Are there any additional components inside, or is the PCB just blank with a few wire links?
Can you take a photo of the inside of the boxes in photos 2 & 3?

Edited by adebov (Mon 02-Jun-08 20:51:48)

You already have an nte5 as shown in picture 2.

it's free for the disabled, although RJ says you have an NTE5 anyway.

Why not change the PSU or monitor on the offending PC as they're the likely culprits.

Thanks for the quick reply Ade, just took a couple of new photos as suggested:

Internals of the master box (from photo 2 in 1st post)
Now that I've opened this - is that the 'test socket' here? Would this be the socket to use to see what the best sync available on the line would be? I can fit a new face plate here, but I'm paranoid about damaging BT property if I try to re wire it ...

In case it's relevant - there used to be a 2nd line here, though it's now disconnected.


Internals of the accessible 'master' socket (from photo 3 in 1st post)
I don't know what I'm looking for - maybe it is just an extension.

Thanks yarwell & RJ

I'm not keen on replacing the monitor (it's <12 months old) & PSU as that won't fix the underlying problem - though the computer may get replaced anyway in the next year.

Well if NTE5 is configued as it should be then I guess I will have to resort to attempting to fit a new faceplate myself or paying the full call out charges...

While I was searching for infomation about this I saw mention of BT66 boxes & 'star wiring' being an issue for ADSL. Is this the type of box I have on the outside wall (photo 1) Would replacing this with something newer be advantageous? If I end up paying for BT to come out I'd like to know in advance everything that might be done to improve the line quality

Now that I've opened this - is that the 'test socket' here?

Yup.
As RJ has mentioned, this socket is a master.

You can test things, by plugging your router (using a micro-filter) into the internal 'test' socket.
If things improve, that's the way to go.
You can't leave it like that, of course, because with the front cover removed, your extension socket is disconnected.

but I'm paranoid about damaging BT property if I try to re wire it

The wires sticking out the front (once you've removed the lower front section) are your property.
This is an NTE5 socket, and is designed to allow anyone to terminate phones & extensions into the removeable front cover, without tampering with the BT network side of things.

The other "master" socket (photo 3 in the first post) is not a master, it's a plain old extension socket.

Edited by adebov (Mon 02-Jun-08 21:53:35)

Replace the front plate on pic 2 with a filtered faceplate. This is an nte5b and is the end of the Openreach network. Although, the source of your problems appears to be noise coming from a computer rather than a fault on the line, so maybe tackling the root cause would be beneficial.

I'll get a new face plate with built in filters & try that Do you recommend any particular brand with the interstitial plate built in?

As for the 'noisy' PC - I'm sorry I wasn't clear in my outline of the problem, yes this is the worst culprit and it will eventually be replaced, but there are other less freuqent losses of sync that definitely aren't due to the PC. My thinking was that if the phone line could be filtered, or the extensions that pick up the interference can be removed such that the the problem PC can be used without issue, then I will be much more confident that I've eliminated dodgy electrical appliances as cause of line noise.

Edited by deleted (Mon 02-Jun-08 22:32:11)

I have only had experience with the BT ADSL faceplate so I can't say which of the retail versions is the best.

In reply to:

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that won't fix the underlying problem

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if switching on this PC causes noise and slower sync speed, then it surely is the underlying problem.

As a quick test I've plugged my router directly into the test socket. Tried booting the bad PC a couple of times & the connection hasn't been broken. It's not a definitive test, but it suggests the extension wire is picking up the inteference (will test again tomorrow with the dodgy PC reconnected to the router & in the same room) If the wires do pick up interference then it's quite possible that they also pick interference from other sources outside my control e.g. neighbours electrical appliances or passing cars/motorcycles.

As a side note I've noticed that the connection stats haven't changed after connecting to the test socket? From the Netgear 834G v2 router:

Line Attenuation: 56db up & 15.5db down
Noise Margin: 11db up & 17db down

Is there a discrepancy on the up/down stream line attenuation ratio - should downstream be circa 30db if the upstream is correct at 56db? (located approx. 2.8km from exchange as crow flies)

I need to try changing the cable between the router & phone socket as it's excessively long @ 10m, but I'll need to buy one tomorrow before I can test that.

Edited by deleted (Tue 03-Jun-08 00:39:12)

In reply to:

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I've noticed that the connection stats haven't changed after connecting to the test socket

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was the speed the same ?

In reply to:

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Line Attenuation: 56db up & 15.5db down

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Either wrong stats or incorrect reporting there. Have seen 15.5 dB downstream occasionally - perhaps a bug or a data exchange issue between modem and DSLAM.

Speed was indeed the same - 2300kbps. I tried resetting the modem at 07:55 this morning & it's 2560kbps. I think 2560kbps is as good as it gets currently. The previous 2900kbps was 1-2 months ago & I think the quality has gradually degraded. The area is fairly rural & susceptible to atmospheric conditions (analogue TV quality varies considerably) and there are frequent power cuts during bad weather, which is pain as the bad weather is also pretty frequent...

Once I've done as much as I can to stabilise the line quality I may try one of the 2wire or Speedtouch routers or modems to see if more speed is available. Is it worth contacting Plusnet before I buy a new modem, would they know in advance which is likely to be a better match for my line?


Edit: I've re connected the extension & the speed has now dropped back to 2100kbps

Edited by deleted (Tue 03-Jun-08 09:25:14)

Seems pretty clear your extension wiring is a factor here. As suggested, a filtered faceplate and locating the router right next to the master on a short cable will probably be the best answer speed-wise.

To move the network around the house, wireless or (my favourite), homeplugs.

Might also be worth carefully checking the rear of the master socket for poor or corroded connections.

As to the 2wire \ speedtouch choice, I would suggest buying one of each and trying them - they both do well, but which is best on a particular line may well be down to luck of the draw. Shopping carefully should net you a pair for under �50 easily, and you can resell the one you don't want. (My 2wire cost me about �15 delivered IIRC)

For the network I think I'm going to install some new CAT6 & go Gigabit LAN (I've got to re route the cable anyway to accomodate the new router location) of course that means an extra headache figuring out the best modem+router combination. D-Link's Gamer oriented routers are quite appealing, but of course that means identifying a different modem only device than the 2wire/Speedtouch routers already mentioned... unless the speedtouch's or 2wire's can be made to operate as a modem only?

I started looking at the connections on the BT box on the outside wall - it's in a pretty messy state , opened it up to find lots of cobwebs & spider nests. Your comment about the corroded connections reminded me that I need to replace the Sky TV cable from the dish, that's decayed after 10 years to the extent that the signal drops in bad weather (the 1 year old 2nd run for Sky+ is fine) So given that part of the phone line is exposed to the same conditions outside it may well be in need of some work too.

Edited by deleted (Tue 03-Jun-08 23:03:32)

You've said the wiring in the house is flaky, but I was wondering if the room with the suspect PC has an energy saving light bulb. As they can cause all sorts of problems. If there is one fitted, try a normal 60watt bulb and then re-run the tests.

In reply to:

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if switching on this PC causes noise and slower sync speed, then it surely is the underlying problem.

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My thoughts exactly. Put a new power supply in the PC - �20 or less, job done !

But by all means do something about the phone wiring too !

Some kind of upstream thottling? Be's old 'Lite' package did that. Gave me a stonking 48db atten. now that I'm on a more expensive package the upstream atten. is reasonable.

Thanks zebedee, I still think that doing that is just a stop gap measure, especially as there is no way for me to identify & control other sources of interference not under my control. Once I'm satifisfied that I can run the noisy PC without affecting snyc I'm probably going to feel reasonably confident that the line isn't behaving as an antenna for electrical noise. At that point I can happily bin the old PC PSU & get on with addressing any other issues

Andrue,

Maybe re throttling, I'm with PlusNet. There are weird things going on with their traffic shaping e.g. I'm finding that my p2p gets momentarily throttled to 0 at regular times: 12am, 1am, 2am etc. No explanation so far from the Plusnet support forum but it's not something I feel I can chase while I know there are line quality issues on my side.

Lately Plusnet been very helpful & responsive with other questions. Once I've done everthing possible from my side I'll get them to look at the line from their side.

Edited by deleted (Wed 04-Jun-08 15:21:52)

silvryn,

Interesting - we do have some energy saver bulbs & I did try switching all the lamps on & off individually to see if there was a faulty lamp somewhere. Can you point me to any more info about this? I may see if a combination of energy saver bulbs together can cause a loss of sync.

I have inexplicably lost sync a few times for some reason definitely not due to the dodgy PC

As for the dodgy PC itself, we thought at first it was a Windows service starting up that caused the router to lose sync. But then after disconnecting it from the router the problem persisted, so I experimented booting it up in different rooms, no monitor or LAN connected. 100% of the time in any room of the house, 10-20s after switch on the router would lose sync

It definitely sounds like a faulty power supply on the PC and while it may not seem like a priority to fix it, bear in mind that it may be corrupting data on your computer and hence to other computers connected to it on your network. a new power supply is available from Ebuyer for around �10 so not much to loose.
It might also be helpful to disconnect the ring wire from your phone wiring as this reduces noise pickup.

The mantra amongst emc engineers with interference is to remove it at source, not try to mop it up elsewhere. With respect, I think that sorting out this PC which is a known source of noise is likely to be a great deal more successful than what can be a somewhat intangible local wiring issue.

Your noisy PC is electrically connected to your LAN via the mains and it is physically proximal; it's unlikely that any external source of interference would enjoy such a high degree of intimacy with your network.

Thanks Xris, the PC is going to be replaced anyway as it's old. For now I thought it would be ideal to keep it as the benchmark while I fix the wiring. For the reasons you state I figured that no other source of interence would likely be as strong as the PC. Therefore if I can stop loss of sync due to that PC, I would likely also prevent or mitigate loss of sync due to other EMI sources? or do you really think that would be a waste of time given the complexity of electromagnetic interference?

Your best way of eliminating the possibility of noise pickup by your extension wiring is to eliminate the extension wiring. The ideal situation would be.....

Filtered faceplate in master socket (good quality one, e.g. ADSL Nation)
ADSL router connected directly to ADSL output on master socket by short cable
DECT phones connected to PHONE output on master socket
ALL other extension wiring removed
Router connected to PC's by Cat5e cable, wi-fi or via Homeplug power adaptors.

Failing that, as an absolute minimum you should disconnect the ring wire on all the house extensions, and disconnect all the extensions that you don't need.

And replace that power supply - it could be affecting your neighbours too, and it's illegal to knowingly cause interference to public services.