What about the bottom line of the post?

Evening Candy123

The Line Attenuations are basically a natural result of the quality and length of the line; and in general terms, the ISP and BT Openreach have no control over those aspects, other than by, say, replacing the whole line or parts of it, at generally relatively high cost, because it would involve replacing multi-way cables, with possibly 400 customers on the end.

BT Openreach legally is only required to maintain it to a standard suitable for land-line phones, not any other function, unless with a very specific contract.

In part, those attenuations can be affected by the state of the (many) joints in each line, particularly if significant noise can be heard when using a simple, directly connected phone - specifically not any form of cordless phone.

Additionally, the attenuations can vary with the weather, particularly when used for the higher-than-audio frequencies involved in Broadband.

The basic telephone wiring system was only expected to handle from about 40 Hertz to about 4,500 Hertz, a restricted part of the audio-frequency range, which depending on one's hearing ability can range from about 25 Hertz to 20,000 Hertz, BB being even higher.

I am constantly amazed that Broadband signals are bring transmitted through the phone system, in some cases on wiring installed 100 years back. My own line is "only" 46 years old; and I remember in the 1970s, GPO Telephones (BT's predecessor) replacing phone poles and wiring in Birmingham when they were about 110 years old.

All else being equal, the higher the line attenuations, the slower your Broadband will be.

They are not capping you. With them this is the best you can get.

Attenuation is just a measure of line distance. So the ISP will not come out, dig up all of the roads and replace your line with a longer one.

The attenuation can go up when you change routers (some measure it differently). Also when you switch ISP you can connect to equipment in the telephone exchange which is further away. Say your old ISP had 50m of cable in the exchange. Your new one may be 150m of cabling away. So this can change things a little. It's not a case of the ISP capping you, it's a case of this is where the available space was in the exchange when the ISP arrived and this amount of cabling was needed to get there. This generally doesn't affect things much though.

Overall your lines perfect, it's not under performing. You did get a little better on the previous ISP but you are not with them anymore. It's different equipment, different provider (so backhaul can be better or worse) & there's been a time lapse. So it's possible that overtime due to work at the exchange etc that your lines been made slightly longer hence a slower speed.

Taking the previous ISP out of the equation and the previous stats out of this... Based on what we see today there is nothing wrong at all. It's performing as it should, within the estimated speed etc. This is the viewpoint any ISP will take.

Sorry i dont agree with your last paragraph as my minimum speed is 6.5mb-14mb with estimate of 8mb whilst checking most sites including BT and the current provider, so you cant say its normal.

In reply to a post by candy123:

why cant they increase my actual bandwidth instead of tweaking the snr margin.

Cuz, on a particular line, they are intimately related. The lower the Target NM the higher the sync speed and v.v. Most ISPs allow the Down Target NM to do down to 6dB or even 3dB on stable lines. The up stats are generally independent of the down ones.

Your current down sync is reasonable for your attenuation; maybe 1 Meg shy of what it could get but acceptable.

Your up sync is being damped by the high 24dB up NM. Best try rebooting the router to see if it will improve (despite what ISP tells you the odd resync wont harm).

That's only an estimate. Your actual 7 Meg sync speed is within that range:

In reply to a post by candy123:

my minimum speed is 6.5mb-14mb with estimate of 8mb

Not the best but acceptable.

Edited by XRaySpeX (Sun 18-Aug-13 19:50:16)

In reply to a post by candy123:

Sorry i dont agree with your last paragraph as my minimum speed is 6.5mb-14mb with estimate of 8mb whilst checking most sites including BT and the current provider, so you cant say its normal.

Believe what you like. Based on the stats you posted here...
"Current figures
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 509 / 6.998
Output Power (Up/Down) [dBm]: 12,4 / 18,0
Line Attenuation (Up/Down) [dB]: 24,2 / 42,0
SN Margin (Up/Down) [dB]: 24,3 / 4,3
through speed 5.2-5.5mb ish."

SN margin of 4.3 is already very low for a 42db line. If you lower this much further the line will just keep dropping out. The only way you can get more speed is if the SNR is lowered, but then you will probably see instability. Even short lines normally have a 6db noise margin target, you are already below this indicating your lines being squeezed for speed.
You can get more upstream speed but not more downstream.

The BT estimates are just that, estimates. BT only guarantee you a voice line. They are not under an obligation to give you x speed... If you got a new line you would prob see higher, you might not though. On your CURRENT line it's behaving okay. In an ideal would I would expect a sync around 8000kbps, you have a sync of 6998. It's slightly below my ideal world figure, but then the worlds not ideal. There's external interference, theres crosstalk from neighbours lines, theres poor internal wiring, the cabling to the exchange is worse than perfect, there's aluminium in the lines, some new lamp posts are installed near to the BT lines (hence more interference), etc etc.

A line which was capable of extra speed would be like this

Current figures
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 509 / 6.998
Output Power (Up/Down) [dBm]: 12,4 / 18,0
Line Attenuation (Up/Down) [dB]: 24,2 / 42,0
SN Margin (Up/Down) [dB]: 24,3 / 15.0
through speed 5.2-5.5mb ish.

If your stats were like this above, with a noise margin of 15, then it indicates there's plenty of extra speed that can be provisioned on that line. As your stats ARE NOT like this and the SNR is 4db, it indicates very little, if any extra speed can be provisioned before instability sets in.

Edited by ukhardy07 (Sun 18-Aug-13 19:56:15)

In reply to a post by candy123:

Bandwidth (Up/Down) [kbps/kbps]: 1,213 / 7,838
Line Attenuation (Up/Down) [dB]: 22.5 / 38.5
SN Margin (Up/Down) [dB]: 7.0 / 6.5

You weren't even getting the best from your old ISP. That line with that attenuation should be getting about 10 Meg. So you were even then over 2 Meg shy.

You line must be below average par quality and this is similarly degrading your speed now on your current ISP.

In reply to a post by candy123:

Sorry i dont agree with your last paragraph as my minimum speed is 6.5mb-14mb with estimate of 8mb whilst checking most sites including BT and the current provider, so you cant say its normal.

ISP sets the SNR target margin, DSLAM and modem do the best they can in terms of speed to meet it. There's no manual intervention beyond setting the target margin. Their action in your OP was correct.

You can try different ADSL flavours, different kit, resync at favourable times or tweak the SNR margin with some modems etc. These can affect the sync speed somewhat.

http://www.coolwebhome.co.uk/calc/calculator.php

Downstream Connection Speed(Kbps) 6300
Downstream Attenuation(dB) 40
Downstream Noise Margin/SNR (dB) 9

i get following results
Target Margin: Estimate
9dB : 6300
6dB : 6990
3dB : 7756

Normal speed range at 40dB attenuation is 8000 Kbps to 11200 Kbps

BUT AFTER UPGRADE OF LINE CARD AND THE NEW ROUTER THEY SENT ITS:

Downstream Connection Speed(Kbps) 6990
Downstream Attenuation(dB) 42
Downstream Noise Margin/SNR (dB) 6

i get following results
Target Margin Estimate
9dB 6299
6dB 6990
3dB 7755

Normal speed range at 42dB attenuation is 6500 Kbps to 10000 Kbps

so same results but at 42 db its 6.5-10mb and 40db its 8mb to 11mb...so i cant ask them to put me to 3 db as it may dropout.

just checked my router stats and its snr margin now midnight is 1.7db still holding sync.