Consistent fault that my ISP has not yet diagnosed

I would appreciate some opinions on the likely cause of the following set of results.
First, a little background.
I live about a mile and a half from my local exchange.
I usually sync at around 3500-4000Kbps and have a 50db down attenuation.
I have been with a well known and, I think, reliable reseller for a number of years and the service has been faultless.
A month or so ago I was moved to the 21CN system and almost immediately I synced at a much higher rate, over 5000Kbps and my throughput down and up increased a lot.
This was great for a few weeks until suddenly I noticed the download rate falling of markedly in the evenings and weekends. I raised the matter with my ISP who, after a week of having me run test after test has now decided that I have a local issue and want to send a BT engineer to check my equipment at a possible cost of £200 or more.
Before I risk what is not an insignificant sum of money to me, perhaps those among the forum could suggest if it is likely to be local. I also fear that the BT engineer will turn up at 10am on a weekday when all is working well.
My adsl router is a Thomson Speedtouch ST585
It is never turned off, except on occasional and rare lockup or power cut, is presently synced at 736 / 5,440 and my profile a week ago was 4000 but is presently 3500.
Here are my results for the last seven days.
(BT) is BT speedtest
(ST) is Speedtest.net

Any opinions would be welcome.
Sorry about the crazy formatting but I hope it is comprehensible.

Date Time Down Up
Monday
17th Jan 10:26am (ST) 4.81Mb/s 0.59Mb/s
18:26pm (ST) 0.72Mb/s 0.59Mb/s

Tuesday
18th Jan am (BT) 4576 Kbps Not Tested
17:50pm (BT) 545 Kbps Not Tested
17:45pm (ST) 0.67Mb/s 0.59Mb/s

Wednesday
19th Jan 12:45am (ST) 4.62Mb/s 0.56Mb/s
12:50am (BT) 4482Kbps Not Tested
17:20pm (BT) 186Kbps Not Tested
17:21pm (ST) 0.51Mb/s 0.60M/bps
19:33pm (ST) 0.55Mb/s 0.58M/bps

Thursday
20th Jan 14:40pm (ST) 2.33Mb/s 0.60Mb/s
16:05pm (ST) 2.60Mb/s 0.60Mb/s
16:15pm (BT) 3400Kbps Not Tested
16:35pm (ST) 0.85Mb/s 0.58Mb/s
17:39pm (BT) 405Kbps Not Tested

Friday
21st Jan 14:42pm (ST) 4.82Mb/s 0.56Mb/s
18:30pm (ST) 0.27Mb/s 0.59Mb/s
18:35pm (BT) 157Kbps Not Tested

Saturday
22nd Jan 10:04am (ST) 2.01Mb/s 0.60Mb/s
10:09am (BT) 1850Kbps Not Tested
14:50am (BT) 553Kbps Not Tested
15:50pm (Broadbandchoices)
0.5Mb 0.6Mb
18:05am (ST) 0.78Mb/s 0.59Mb/s

Sunday
23rd Jan 10:14am (ST) 1.31Mb/s 0.60Mb/s
13:04pm (ST) 1.79Mb/s 0.58Mb/s
17:12pm (ST) 0.40Mb/s 0.61Mb/s
17:18pm (BT) 247Kbps 585Kb/s

Monday
24th Jan 09:46am (ST) 4.27Mb/s 0.58Mb/s
09:54am (BT) 3459Kbps Not Tested
19:10pm (ST) 0.43Mb/s 0.57Mb/s
19:16pm (BT) 294Kbps Not Tested

The ping is consistently around 85-100ms

Edited by deleted (Mon 24-Jan-11 23:48:42)

Can you post your full router stats? and possibly the full result of a BT speedtest?

Matt

Also at what time of the night does it improve, if around 1am, then its congestion based and probably nothing to do with the connection.

You should only get the £200 charge if the engineer finds a fault that they fix on your side of things, e.g. a phone plugged in without a microfilter.

In reply to a post by uno:

Can you post your full router stats? and possibly the full result of a BT speedtest?

Matt

Sure Matt,

Router Info--------------------
Link Information

Uptime: 3 days, 2:58:39
Modulation: G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]: 736 / 5,440
Data Transferred (Sent/Received) [MB/GB]: 140.20 / 1.75
Output Power (Up/Down) [dBm]: 12.5 / 19.5
Line Attenuation (Up/Down) [dB]: 27.0 / 50.0
SN Margin (Up/Down) [dB]: 11.0 / 5.5
Vendor ID (Local/Remote): TMMB / IFTN
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 2 / 0
FEC Errors (Up/Down): 0 / 1,153,387
CRC Errors (Up/Down): 0 / 1,598
HEC Errors (Up/Down): 0 / 1,449

------------------------------------

BT test 23:45 24th -------------------

Results Image not loaded

Test1 comprises of Best Effort Test: -provides background information.

Download Speed
2953 Kbps

0 Kbps 4000 Kbps
Max Achievable Speed

Download speed achieved during the test was - 2953 Kbps
For your connection, the acceptable range of speeds is 1200-4000 Kbps.
IP Profile for your line is - 4500 Kbps
The throughput of Best Efforts (BE) classes achieved during the test is - 11.86:24.24:63.9 (SBE:NBE:PBE)
These figures represent the ratio while sententiously passing Sub BE, Normal BE and Priority BE marked traffic.

The results of this test will vary depending on the way your ISP has decided to use these traffic classes.


If you wish to discuss these results please contact your ISP.

If you are experiencing problems with specific applications, servers or websites please contact your ISP for assistance.

Your test has completed please close this window to exit the performance tester.

Note: An Upstream test was not conducted on this line due to a technical issue. If your concern is related to upstream performance then please retry
the performance test again in 1 hours time.

--------------------------------

I'd be happy with this result if it was consistent.


Larry

Some errors on the downstream, which can indicate an issue.

Could you explain how the router is connected to the phone socket and if this is the main socket, an extension or the test socket?

Matt

In reply to a post by MrSaffron:

Also at what time of the night does it improve, if around 1am, then its congestion based and probably nothing to do with the connection.

You should only get the £200 charge if the engineer finds a fault that they fix on your side of things, e.g. a phone plugged in without a microfilter.

I have actually just done a BT test for Matt, (results posted) and this is the first time I have checked it later than around 22:00.
It is pretty good for my location and much improved over earlier tests this evening, (see my first post).

Larry

In reply to a post by uno:

Some errors on the downstream, which can indicate an issue.

Could you explain how the router is connected to the phone socket and if this is the main socket, an extension or the test socket?

Matt

It is connected directly into the BT socket with a filter which also has a BT phone attached.
The BT socket is maybe too old to have a test socket, circa 1980, but I may need to look.

I might also add that the Line Attenuation down often drops to 4.5db which may account for some of the errors but even with this poor LA I have often achieved around the 4000 on the 21CN setup whilst anything less than 6db would cause trouble on the old exchange setup.

Larry

Edited by deleted (Tue 25-Jan-11 00:00:17)

Do you have any extensions in the properly or is this the only socket?

Matt

In reply to a post by uno:

Do you have any extensions in the properly or is this the only socket?

Matt

No, the router and the phone are the only connections and the PC is connected by ethernet from the router.

Larry

I'd still have a look for a test socket, in case the faceplate has become faulty.

Have you also tried a different equipment?

Sorry for asking the obvious.

Matt