Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[terryc]

Earlier in the year via advice from this forum, I managed to get BT to finally resolve an issue with a reduced sync speed  at 4.5Mb (profile 4Mb) instead of the normal 6.5 (ish) Mb and corresponding IP profile of 6.0Mb It took a while and and email to Ben Verwayens office but eventually my profile was reset to 6Mb and I can sync at around 7040 with an occasional drop (downstream SNR varies between 7db and 2db so the line isn't perfect with downstream attenuation of 45 db. (Interleaving is off)

However, no matter how many time I lose sync it always re-syncs at a high rate and doesn't drop to a lower speed which is what I would expect (together with raised SNR) to try and stabilize it? I'm using a Netgear DG834 which I know "hangs on" well but yesterday I tried my new Home Hub (s/w v 6.2.6c) which immediately connected at 8Mb but then after about 2 hours (into the evening) gradually re-synced down to 4.8Mb fearing that my profile would have gone back to 4.5Mb or worse, I reconnected the Netgear - re-synced at 7040, checked BT Speedtester and still had a profile of 6Mb.  Which is what I don't understand. I checked again this morning and I'd lost sync 4 times in less than hour overnight but it's still at 7040 and my profile is still 6Mb.

I know when I spoke to BT high level complaints earlier in the year they said they had "fixed" the profile - maybe they meant fixed in that it will never reduce, rather than fixed the problem!  Is this possible - can it be set not to reduce?

I'd really like to use the hub for the hub phone, but don't want to risk dropping speeds as result.

Any thoughts please.

Many thanks

Terry

[Broadband1]

Hey there in the past the BT Home Hub has been known to drop sync speeds but that for some Hoome Hub users is because of the v6.2.6 it for some unknown reason does that so I could recommend you downgrade your HomeHub like I have I would be please to help in any way.

[terryc]

Thanks Broadband1 - I've been doing some more tests and overnight using Routerstats on the Netgear I see the SNR drop from around a 6db to 0db on a number of occasions although it doesn't always lose sync - testimony to the Netgear I suppose.  The interesting thing is that the SNR starts to drop when a street lamp right outside the house (which is also within 2m of the BT DP  a "ground level" grey box) comes on, and improves at the time it goes off.  I know this is an acknowledged problem but what the cure is I don't know - it hasn't always been like this so maybe I can persuade the council to change the lamp!  So I think until I get that resolved, the HH is not worth trying as I doubt it would work down to the noise levels the Netgear is doing.

Terry

[roseway]

That's an interesting observation about the street lamp. It's often said that they can cause ADSL interference, but you don't often get such a definitive example. I guess that a complaint to the council would be worth trying, although you might have trouble getting anyone to understand what you're talking about.

[Broadband1]

Have you tried waiting till dark and throwing a rock at it  might work. I have had this problem before during the night my Attenuation would increase severly and SNR dropped to about 6.5db just enough to keep sync on the HomeHub it took an engineer to come round in the end he concluded that street lights were the problem and seeing as I lived in a private estate it was one quick phone call to the landlord or whom it may consern, But if you need to contact a Local Council that could get you in a 2 & 8

[guest]

Techie bit approaching :

Street lamps are usually just low-pressure sodium lamps with a ballast at the base of the post.

The old fashioned ballasts are coil & core and operate at mains frequencies (50Hz) so they cause zero interference to ADSL when they are running. The problem is that the core losses in the coils increase over time and the ballasts are at best 80% efficient when brand new. They can cause impulse noise when they turn on/off which might affect some marginal ADSL lines. Flickering lamps will be putting out a lot of interference over quite a wide range of frequencies.

As the older ones fail (or when councils can afford it) they are being replaced with electronic ballasts. Now the main advantage of these is that they are a minimum of 85% efficient but they have other advantages such as being able to drive a lamp which is physically further away (think "taller lamppost") and also increased lamp life due to softer starting techniques. The problem as far as ADSL goes is that the electronic ballasts drive the lamps at frequencies ranging from around 200kHz all the way up to 2MHz (unusual). Provided the ballast and the associated cabling is all properly screened then it doesn't radiate too far - a couple of metres perhaps and should present little problem. However that's on current ballasts. The first few generations of electronic ballast were pretty bad for causing interference but who noticed back then? The interference was on MW radio frequencies which were worse at night anyway.

I bet if you pointed a portable (MW) radio at the lamppost and tuned for worst interference, then if you walked towards the lamppost the interference would get louder. A bit of trial and error would be needed here.

You would need to either find someone who knew what you were talking about at the local council or somehow get BT Openreach interested. I'd have thought they should be able to get it resolved with the council although I wouldn't imagine it'd be immediate.