Lower than expected speeds due to high SNR

[dcwt2010]

No idea there was a business forum but here's what's happened so far

http://community.bt.com/t5/BB-Speed-Connection-Issues/Lower-than-expected-speeds-due-to-high-SNR/td-...

So, how do I contact the mods on here then? They were pretty nifty on the residential forums (replied today when I sent the message on Sat, pretty good considering it's still Bank holiday!) but I got told that my issues have to be handled by the business BT team.

Basically, my connection can't seem to hold sync at above 1760 kbs; during night time when the SNR drops (due to increased electrical usage etc) if I had the connection syncced at 2Mbs or above (highest I've seen is 2.4Mbs) then it will lose connection and resync at ~1760kbs. My estimated linespeed is 2Mbs but I'm not really seeing that and it is frustrating. With a 52 db downstream attenuation I should see up to 4Mbs but obviously that's dependent on perfect conditions.  

Anyway, loads of details on that 4 page thread I won't repeat myself on here.

PS I tried to use this page 

https://secure.business.bt.com/FaultManagement/Online/M701AuthenticateViaBBNumberWithCaptcha.aspx?fa...

I put in our number but it came back as unrecognised, what gives?

[dcwt2010]

Requested an SNR reset via tech support on the phone. Pretty easy although the guy kept insisting that the best my line could do was 500kbs to 2Mbs! I wouldn't mind but I told him point blank that nearby houses could get ~3.6Mbs, although I'm only aiming for ~3 Mbs which, with a 52 db downstream attenuation, I should be totally able to do so.

I put in a new router TD-W8960N and guess what? The Homehub 2 was lying, I seem to have a 60 db downstream attenuation now so  2 Mbs really is my max capacity... unless the new router is wrong?

[MHC]

There is no consistency in the way downstream received power and noise is measured - and some use the absolute figure, others the margin allowing for the 6dB needed for sync ...   Then the termination impoedance is not always te same which can further affect the figure ...

If you can find a 2wire2700HGV-C on ebay at a reasonable price, go for it.  They are very stable on long / hi atten lines and may give a little more speed.  They also sync at 3dB once a line is seen as stable and will hold down to 0dB.

[dcwt2010]

I think I will keep my TP link for now but thanks for the suggestion. It's certainly more sturdy than the HH2! Below you can see where the SNR just dives to 0 db but the connection doesn't seem to have broken! Also, the SNR hasn't dropped even though we are now well into the night. 

I do find it frustrating that these stats are not comparable to the Homehub...

So how the heck can I work out line length if not from downstream attenuation? HH2 and this TP link router show 8 db difference... that's pretty significant, no?

[kuerten]

8db sounds normal to me but it should be better than that though.

[dcwt2010]

I think you misunderstood what I said;

HH2 shows downstream attenuation as 52db

TP link TD-W8960N shows it as 60/61db.

The difference in potential sync speed is really significant and seeing as with the HH2 I never got better than 2.3 Mbs sync I'm inclined to believe that the attenuation is ~60 db which is really quite disappointing.