Getting the very most out of my connection (672 Kbps ADSL)

I've just moved to a new property and unfortunately the broadband performance is very very slow

BT have sent an engineer out but the upshot was that the line is as good as it's going to get and theres nothing that can be done beyond an infrastructure improvement (scheduled for the next couple of years so not a lost cause!). The engineer mentioned that interleaving is off and that the connection has no CRC errors (i.e. is very stable albeit slow).

Because of this I'm now trying to eek every last byte out of the connection that I possibly can.

Current Stats:
Link Rate - 672 Kbps (Down) / 416 Kbps (Up)
Line Attenuation - 63.5 dB (Down) / 31.5 dB (Up)
Noise Margin - 6.0 dB (Down) / 5.0 dB (Up)

Line:
I'm connected to this exchange - https://www.samknows.com/broadband/exchange/EASTM - which is an approximate 6.13KM (straight line) distance away.

Current hardware:
New BT master socket
ADSL Nation XTE2005 filtered faceplate (I also have a new Openreach MK3 faceplate I could use instead)
0.5m Tandy "ADSL Nation Pro+" twisted pair RJ11 cable
New Netgear modem router (think something like the Nighthawk).

My current modem doesn't support SNR adjustment (i've tried using telnet but it kills the connection no matter what).

I've just bought a Billion 8800NL based on the fact that it looks to be the best (or at least joint, with the same modem chip as the 7800NXL) modem I can buy, and that it supports SNR adjustment.

Is there *anything* else I can do?

Edited by deleted (Sat 11-Apr-15 09:49:55)

The line attenuation figures look the wrong way around since upstream attenuation is usually less than downstream due to the very different frequencies used.

At 6km straight line you might might be 8km of cable or 12 km so yes are probably the best you will get.

With 5dB noise margin on the downstream there is no much scope for noise margin adjustment.

D'oh, I completely messed the figures up - I've revised them in the first post.

I know that with such a long line it's going to be very difficult to get a large improvement - but even 5% would be a start.

Pushing down to a 3dB may be OK - the key will be whether the 6dB is stable, i.e. does it vary at all between day and night?

If you PM your postcode can see assess likely actual line length, since if its close to 8km chances of improving are probably higher, but if 12 km I'd not waste the time.

I would have suggested buying an unused 2wire 2700HGV from ebay.

Experience has shon them to be excellent on very long lines and they will train down to 3dB if the line is seen to be stable. They will also hold the line at 1 or2 dB which helps with overnight changes.

When I installed one on a friends 9++++ km line we managed to get the initial 900kbps downstream up to near 1.5Mbps.

In reply to a post by MHC:

I would have suggested buying an unused 2wire 2700HGV from ebay.

I've got one sitting in a cupboard if Jakg would like to PM me.

See my reply to MHC - I have a 2700HGV if you'd like it for the cost of postage.

Ok perfect - I've just picked one up on eBay for a fiver.

EDIT - Apologies - just seen the above posts! Thanks for the offer but I've just bought one.

Edited by deleted (Sat 11-Apr-15 19:07:41)

In reply to a post by Jakg:

EDIT - Apologies - just seen the above posts! Thanks for the offer but I've just bought one.

Back in the cupboard it goes then, not worth selling it for five quid less all the fees!

If you are not on BT and need to add a username and password for your connection.....use the PAGE=HURL13 method....http://bt2700hgv.tripod.com/063.htm

Ian

I was going to add a similar comment .... Unlocking is fairly simple.

And even if it does not give a large improvement, the 2700 makes a good WAP!

An update to this.

I bought a 2Wire 2700HGV on eBay - but unfortunately it showed up with the wrong power cable. Not such a bargain after all!

Once I get my money back (or maybe even the power cable?) I'll try to pick one up for testing.

In the mean time, my IP profile somehow ended up at 212kbps and my connection is still "recovering". BT did an IP profile reset which got it back up to 544kbps, which was worse than before.

I bought a Billion 8800NL modem router and fitted it, and unfortunately things got even worse - I went to 480kbps (I've been careful to try to make each disconnection "clean" by disconnecting rather than just pulling the plug, and spacing any disconnections more than 3 days apart).

I've since dropped the SNR to 5db (from 6db), reconnected and I've gone up to 576kbps. Unfortunately I don't know how much of that is the reduced SNR vs the effect of just reconnecting to see if I get a higher speed.

Having got a better modem I can now provide some better info:

Router stats (from the modem):
[img]http://i.imgur.com/VppizUL.png[/img]

Router stats (the application):
[img]http://i.imgur.com/0HteCCU.png[/img]

[img]http://i.imgur.com/mAqxxEb.png[/img]

BT wholesale speedtest:
[img]http://i.imgur.com/HoW4rmN.png[/img]

Kitz Line stats:
[img]http://i.imgur.com/vaOFQl5.png[/img]

I've been in contact with BT but theres nothing more they can or are willing to do - after the engineer visit I have a note on my account saying "line works as well as can be expected considering length" and "other properties don't even get broadband" so as far as their concerned thats it. So now I'm on my own!

My next steps are to refit my ADSL Nation filtered faceplate (back on the BT OpenReach one after dealing with BT) and to try dropping the SNR 1db every 3 days.

if I remember correctly, there were power supply problems on these routers,(2Wire 2700HGV ) and everything would look right, - it just didn't work.
I think it needs 5.1v 3amp

Edited by ggremlin (Mon 27-Apr-15 21:36:37)

No - mine has a plug that doesn't even fit so I know it's wrong!

And the BT Broadband availability checker...

[img]http://i.imgur.com/KYfnEgo.png[/img]

The stats for my line are:

Uptime: 1 day, 4:31:42
DSL Type: ITU-T G.992.1
Bandwidth (Up/Down) [kbps/kbps]: 448 / 1,632
Output Power (Up/Down) [dBm]: 12.5 / 16.5
Line Attenuation (Up/Down) [dB]: 31.5 / 63.5
SN Margin (Up/Down) [dB]: 12.0 / 9.5
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / IFTN
Loss of Framing (Local/Remote): 0 / -
Loss of Signal (Local/Remote): 0 / -
Loss of Power (Local/Remote): 0 / -
Loss of Link (Remote): -
Error Seconds (Local/Remote): 62 / -
FEC Errors (Up/Down): 60 / 9,211
CRC Errors (Up/Down): 22 / 92
HEC Errors (Up/Down): -2 / 92 / 568

My line is 6.1km long, from the days when the BT line test showed you this information. The modem is a Technicolor 582n, and I have an ADSL Nation filtered faceplate.

ADSL Link Downstream Upstream
Connection Speed 1760 kbps 512 kbps
Line Attenuation 63 db 15.5 db
Noise Margin 6 db 6 db

Another long E.O. line > 6Kms. downstream attenuation is closer to 72dB

In reply to a post by Brunel:

ADSL Link Downstream Upstream
Connection Speed 1760 kbps 512 kbps
Line Attenuation 63 db 15.5 db
Noise Margin 6 db 6 db

Another long E.O. line > 6Kms. downstream attenuation is closer to 72dB

Does your modem only reports upstream attenuation to a max of 15.5 dB? If so, ignore the next comment.

There is something a little amiss with the attenuation figures especially if your downstream is 72dB. Upstream attenuation is normally in the order of half (numerical) that of downstream so for 72 dB I would expect to see somewhere from 30 to 40dB maybe 25 at the extreme but not 15.5.

Yes the router is in error, normally reports circa 30dB.

Netgear, DG834G v2 running DG Team firmware.

Can only obtain a stable connection on G.DMT and interleaving on.

Dropping the SNR to 4dB results in too many errors and instability.

30 and 72 - they are about right.

See my recommendation in another post.

I have a friend with a line that is in the order of 9 km. With minimal wiring and any local noise alleviated, we have managed to push his speed up to around 1.5Mbps.

Still waiting for my 2700HGV to arrive, so in the meantime another question.

Stats at 5db SNR:
http://i.imgur.com/2EC11qP.png

Stats at 4db SNR:
http://i.imgur.com/sORslLx.png

Speed is better at 4 - but it looks like I've got interleaving on and my line is still getting much more errors (but no disconnects). How do I balance speed vs errors? I think my line would be stable at 3db - but if that means a higher sync speed, more errors but overall less throughput it's pointless.

Another update

Bought a 2Wire 2700HGV (well two with one PSU).

I got a faster connection (1050kbps) but the router appears to lose connection after several hours. The log suggests its going to reconnect, but it doesn't actually seem to do so automatically. I reconnect it, it works for a while - then dies.

Watching the stats it seems to be very aggressive at trying to drop my SNR so I suspect that it's just too aggressive for the line? Confused why it can't reconnect though. I've tried 2 units, both with different firmware versions. Same PSU with both, though.

Back on the Billion 8800NL and getting 800kbps.

Both were using ADSL (G DMT). Will try using ADSL2 later.

I forgot to mention - my DSLAM is Infineon. I've seen online that supposedly your better matching vendors. My Billion is broadcom but the 2Wire used an Infineon chip. Any other good Infineon ones?

Edited by deleted (Sat 23-May-15 21:38:38)

Do you really mean ADSL2, or ADSL2+. Most people saying ADSL2 do mean 2+.

The reason I ask is that in a high proportion of cases, (not all), the attenuation on ADSL2+ will be ~3dB higher than on ADSL, and the reduction in sync speed that causes more than cancels out the gain from ADSL2+ itself.

ADSL2 on the other hand normally gets a speed advantage over ADSL but does not suffer the 3dB attenuation gain. It is therefore frequently the best option on long lines.

Just to add that I cannot get a connection the exchange using ADSL2 (not ADSL2+). It's G.DMT or nothing.

I picked up a DrayTek 120 off eBay (uses an Infineon chipset to match the one in my cab), worse performance than when using my Billion 8800nl.

Specifically, 544/448kbps Up/Down at 8db SNR. I don't know where it got 8 from as my line will do 5 easily, but theres no way I can tweak it to improve on that.

Stats:
--------------------------- ATU-R Info (hw: annex A, f/w: annex A) -----------
DSL Modulation : G.DMT
State : SHOWTIME
DS Actual Rate : 544000 bps US Actual Rate : 448000 bps
DS Attainable Rate : 704000 bps US Attainable Rate : 636000 bps
DS Path Mode : Interleave US Path Mode : Interleave
DS Interleave Depth : 4 US Interleave Depth : 4
NE Current Attenuation : 77 dB Cur SNR Margin : 8 dB
DS actual PSD : 14. 7 dB US actual PSD : 12. 6 dB
ADSL Firmware Version : 332201_A
-------------------------------- ATU-C Info ---------------------------------
Far Current Attenuation : 31 dB Far SNR Margin : 7 dB
CO ITU Version[0] : 00004946 CO ITU Version[1] : 0000544e
DSLAM CHIPSET VENDOR : < IFTN >


(I know I'm flogging a dead horse)

Just to add that I cannot get a connection the exchange using ADSL2 (not ADSL2+). It's G.DMT or nothing.

That is the problem with the 2Wire routers, the modulation mode cannot be set, purely automatic.

I have several 2Wire routers, they used to connect using ADSL2, and were very stable.

Now I have to use G.DMT, any flavour of ADSL, is too flaky.

If you have been disconnecting and reconnecting a lot, as in several times in an hour, the DLM can take exception to that and think it is an unstable line.

It will then hike the sync-time noise margin from 6dB to 9dB, which costs 500-750kbps of sync speed.

If that is the cause, just letting it run as is will normally get a drop back to 6dB and an automatic re-sync back at higher speed after 10-14 days depending on the error rates. That tends to be in the middle of the night, and a single re-sync well inside daylight hours following that is likely to add a bit more speed.