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[Irvin]

Back in January I found out that the line to my house could now cope with a MAX connection. Here's what Tiscali (regrettably) came back to me with when I enquired:

"The download speeds on this product will be the maximum your line can reliably support up to 3Mb. This will depend on the quality of your line and distance from exchange.

I performed certain tests on your BT line & found that it supports a maximum speed up to 2 Mbps"

So I upgraded from a 1mb Fixed to a MAX contract. With a bit of SNR tweaking I got up to getting on for 3mb:

31/01/2008
07:20
Data Rate(Kbps)          2688                    832 
Noise margin (dB)        10.9                    10.0 
Output power (dBm)    11.9                     8.3 
Attenuation (dB)          46.0                    28.0 


All was fine until May when it suddenly dropped back to 1mb. With a bit of treaking again this is the best I've got since then:

Data Rate(Kbps)          1472                    832 
Noise margin (dB)          6.1                    10.0 
Output power (dBm)    11.9                    18.3 
Attenuation (dB)          48.0                    28.0 
 
The attenuation had gone up from 46 to 48 overnight but ther's no affect on the upsteam connection. No problems with the filters (replaced the lot), router (tried 3) or anything else (bell wire trick etc etc).

It's an overhead line and we are in a very rural location but the guy next door to me can get 4mb solid and he's 100m further away from the exchange! We share the same route up to a pole 25m away. My other neighbour used to get 2mb too and now he's in the same boat.

Exchange: Heathfield. BT Code: NDHEA
Location: Station Road, TN21 8LD
Distance:- Direct:    3.06 km
  (appx)* By Road: 3.54 km

Fixed ADSL:  1024 kbps (1 Mb) 
DSL Max :   1000 kbps (1 Mb) 
21CN WBC : Not Available 

Now, I was mad enough to give Tiscali my line rental when I upgraded so I've been battling with them for months asking them to report a fault to Openreach. I got refusal after refusal, lies, insults, swearing, the works, so now I'm back with BT. Before I dial 150 do I have a valid case to report this as a fault??? There are some domestic power lines draped over the phone cable - would this have any affect???

My wife is about to finish an OU degree and she needs to do interactive experiments using SPSS. It doesn't like 1mb at all!!!

If anyone could advise I'd be really greatful.

Irvin

[Ezzer]

The first thing which called out to me was the downstream snr of 10.5db on a fixed speed, it's ok-ish

Target is >9db, teens is average, 20's good, 30's excellent with a figure of 10.5 I would be itching to pay with the internal wiring if there is any although 6.1 snrm is good on max.

2db variation in attenuation with little tweaks is ok and normal

46-48 db is moderate

http://www.kitz.co.uk/adsl/socket.htm this is a good place to start if you havn't already

[Irvin]

Thanks Ezzer,

Just for fun, I've just rebooted by router and here's what I get without any tweaking:

Data Rate(Kbps)          608                    832 
Noise margin (dB)        15.9                    9.0 
Output power (dBm)    11.9                    15.5 
Attenuation (dB)          48.0                    28.0 
   
Downstream slower than Upstream? Does this give you any hints??

Ta!

Irvin

[Ezzer]

snrm jumped a long way. have you got a nte5 (master socket) which you could try plugging into or take the face plate off and try in the test socket ?

[kitz]

Hi and welcome

Your speed is much lower than what I'd expect to see on a 46-48dB line - it should be nearer 5Mb in good conditions.

The higher attenuation will account for some speed loss.. but the loss of attenuation can be an early sign of degradation of the physical line.   
The latest stats dont look good at all - the lower sync speed means that your SNRM has taken one heck of a dive.

Like Ezzer says - are things still the same if you use the test socket behind the master socket.
Also its worth trying the quiet line test (Dial 17070 and select option 2.) to see if you can hear any noise on the line.

[Irvin]

Thanks Kitz - cracked it. Found the master socket and tried the test point - 5mb straight away. The wiring then goes into a home-brew junction box to feed four extensions (we live in an old factory...). These are connected with.... INSULATION TAPE!!!! I'm going to solder the connections which I hope will help. If it doesn't, does that mean that I need to isolate which extension wire(s) are at fault?? Naturally, none of the lines are labelled...

[Irvin]

I've just plugged my router into the Test socket, taken a reading then plugged it into the Master. Here's the numbers:

Test Socket:

Rate 3744
Noise 15.1
Attenuation 46

Master socket:

Rate 1632
Noise 15.1
Attenuation 47

Could anyone tell me if these figures are what I should expect to see or is there too much noise on my cabling?

I've plugged my router into its usual extension socket and wound down the SNR to 10. Here's what its reporting now:

Rate 2208
Noise 10.1
Attenuation 47

How silly would it be to plug a filter into the test socket, run the router from that and splice the extensions into the filter's "phone" socket.

Cheers

Irvin

[jid]

Well as the SNR has dropped by 5dB when it is on the extension it is either the extension is picking up noise or is of poor quality.

Is a round or flat type of cable?

With 46dB attenuation you should expect a sync of around 5792kbps according to this:-
http://kitz.co.uk/adsl/max_speed_calc.php

However it looks like your Target SNR is 15dB if those stats whilst connected to the test socket are straight after a resync.

If it is 15dB, that will be limiting the speed of your line too.

[kitz]

Thoses stats indicate that theres a problem somewhere with your internal wiring.  When you use the test socket it isolates any extensions.
I'd recommend unplugging everything and then adding one item at a time to see if you can locate exactly which part is causing the problem, and replace that.


>> How silly would it be to plug a filter into the test socket, run the router from that and splice the extensions into the filter's "phone" socket.

Whilst not the preferred method, I should tell you that really you should attempt to track down the faulty cable.  However I have heard of at least two who have done similar to what you suggest because they claim it gives them the best connection.
At the end of the day all the internal wiring is the owners responsibility, so................


just make sure you dont change any of the wiring past the demarcation point which BT would have a very dim view of.

* kitz waits to see what Ezzer says.. and what his reaction would be to seeing that sort of set-up

[jid]

* kitz waits to see what Ezzer says.. and what his reaction would be to seeing that sort of set-up

 

[Irvin]

Thanks for your help everyone!

Yesterday I disconnected all of the extensions and connected each one up one at a time, taking a note of the stats each time.

With no extensions added here's what I got:

Master socket
Data Rate(Kbps)          4128                    832 
Noise margin (dB)        15.1                    10.0 
Output power (dBm)    11.9                    19.7 
Attenuation (dB)          46.0                    28.0

Here's the best extension:

Data Rate(Kbps)          2720                    832 
Noise margin (dB)        15.2                    10.0 
Output power (dBm)    11.9                    18.3 
Attenuation (dB)          46.0                    28.0 

And the worst:

Data Rate(Kbps)          2048                    832 
Noise margin (dB)        15.3                    10.0 
Output power (dBm)    11.9                    17.3 
Attenuation (dB)          47.0                    28.0

All of the extensions are round 6-way cables and I've only connected up the 2 & 5 wires each time. Are these figures what I should expect to see or is my cabling shot to bits?

I've connected the router to the best extension (wired to the back of the front plate) and Sky / DECT to the second best (connected via the front socket) and left the rest off as I don't use them.

I've got a Belkin F5D7633UK4 FW:UK_1.00.25 so I've been able to tweak the SNR down to 9.5 giving me a rate of just over 3000Kbps. It's now on an decent shielded cable which should have helped. And I've just ordered a Clarity faceplate so I can make a neat job of the cables and get rid of the (passive) filters.

Cheers!!

[kitz]

Thanks for providing those stats

>> Are these figures what I should expect to see or is my cabling shot to bits?

No its not normal at all..  theres something wrong with the extension wiring.. or its picking up some sort of electromagnetic interference from somewhere 
Some extensions may have a tiny bit of loss - but certainly not that much.

[Ezzer]

So thats why I had a rat breathing in my ear today, it knew my ears would be burning.

Kitz has some good pages on site which may help, first

http://www.kitz.co.uk/adsl/socket.htm

for the other connection point probably getting a block terminal from a diy shop similar to a bt77a or 78a;

http://www.kitz.co.uk/adsl/btsockets.htm

would be a good way round reterminating your internal wiring, and with idc's it gives you an easy means to connect each internal cable inturn and check your stats to identifi which are the problem connections.

If your looking to rework everything via the master socket then why not go for a dsl ssfp. I don't know if there avalable comercialy but we carry data extention kits on our vans for 5,10 and 30m lenghts which is a plug which fits into the dsl output of the dsl ssfp, cat5 type cable which can terminate in a dedicated socket for rj11 cable to the modem/router. due to the fact wireless routers are so common we fit less and less of them but are used if the ssfp on the nte means the modem is in an inpractical area but still seperates the internal wiring from the dsl signal

[Irvin]

Thanks again,

I'll see how much improvement I get (if any) with the new faceplate. Failing that, I'll look at rewiring a dedicated DSL extension with Pro + cable. Pity I'm in such large building - should be fun 

[Irvin]

So here I am waiting for the postman, twiddling my thumbs. So I thought I'd take off the extension faceplates of the two that are now in use, remove the bell and gnd wires (although they are already disconnected at the Master), tidy up the green pair and re-make the connections. What a difference!!!

Data Rate(Kbps)          5248                    832
Noise margin (dB)          9.6                    10.0 
Output power (dBm)    11.9                    19.7 
Attenuation (dB)          46.0                    28.0

I haven't rebooted the router so it's still running with the SNR tweak but even so, I'm happy with that  8)

I couldn't have done it without you!!!