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Standard User zarkrax
(regular) Mon 20-Jul-15 10:38:01
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ADSL Sync speeds getting slower


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About a month ago I was enjoying Sync Speeds of 6700 to 7100

Then I had an issue where BB would not sync and kept restarting so I replaced my Netgear DGN2200 with my home hub v2 to log the fault. When the BB fault was fixed it came back on and re-synced to 6700 then disconnected and re-synced to 6300, finally realising my homehub is probably making things worse I reconnected my DGN2200 and it synced at 6200, then I rebooted and it went down to 6150. So I decided to leave it alone and the line was up for 14 days.

Yesterday I rebooted at midday and it re-synced to 6095 (Still getting slower frown)

I think BT have updated my target SNR from 3db to 6db. hence my slower sync speeds.

I have been monitoring the router stats and after a resync the SNR is initially at 6.3 then after a while goes down to 5.3db and maybe goes up to 5.8db.

So I was wondering:

1. Should I be looking for a SNR of lets say 6.5db (which never seems to happen when the line has calmed down) before I issue a reboot in the hope I get a higher sync rate?

2. How long do I need to leave my line before it will go back down to a target SNR of 3?

Thanks in advance.

Edited by zarkrax (Mon 20-Jul-15 10:53:26)

Administrator MrSaffron
(staff) Mon 20-Jul-15 11:05:08
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Re: ADSL Sync speeds getting slower


[re: zarkrax] [link to this post]
 
3dB targets are only given to lines that see very few errors, so you might never see that target value again.

Trying to second guess the random noise environment is a sure fire way to send yourself mad. General rule if snr margin is say 8dB and you have a target of 6dB then a resync may gain some speed, but things are too imprecise when talking about 0.5 dB changes.

The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User zarkrax
(regular) Mon 20-Jul-15 11:31:41
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Re: ADSL Sync speeds getting slower


[re: MrSaffron] [link to this post]
 
Thanks, Is there any way I can get the 3db manually changed back? The line was ok on this target rate for over 2 years before the fault.


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Administrator MrSaffron
(staff) Mon 20-Jul-15 11:43:33
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Re: ADSL Sync speeds getting slower


[re: zarkrax] [link to this post]
 
Nope

The fact you are now seeing the snr margin varying by 1 to 1.5dB means that you risk resyncs if they set the 3dB again and/or increased error rates.

The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User 961a
(regular) Mon 20-Jul-15 13:52:05
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Re: ADSL Sync speeds getting slower


[re: zarkrax] [link to this post]
 
In reply to a post by zarkrax:
About a month ago I was enjoying Sync Speeds of 6700 to 7100

Then I had an issue where BB would not sync and kept restarting.....

When the BB fault was fixed it came back on and re-synced to 6700 then disconnected and re-synced to 6300.....

So I decided to leave it alone and the line was up for 14 days.

Yesterday I rebooted at midday and it re-synced to 6095 (Still getting slower :

I have been monitoring the router stats and after a resync the SNR is initially at 6.3 then after a while goes down to 5.3db and maybe goes up to 5.8db.

So I was wondering:

1. Should I be looking for a SNR of lets say 6.5db (which never seems to happen when the line has calmed down) before I issue a reboot in the hope I get a higher sync rate?

2. How long do I need to leave my line before it will go back down to a target SNR of 3?


My first observation is that from looking at service status of a variety of ISPs there seems to be a lot of network faffing going on at the moment so resync may be happening to your line quite apart from any you are doing

Secondly, if you are going to reboot after the line is up for 14 days you need to do it at the time of day when it is going to resync as fast as possible. To me that means Sunday between 6am and 9am or similar rather than mid day on any day of the week

With many Billion products such as 7800 you can access a menu to enable you to set the SNR yourself but be advised that you need to use this ability sparingly because every time you resync after the first time you'll need to allow time for the system to settle. 14 days isn't needed but I suggest anything under 3 days will not produce the best result

http://www.increasebroadbandspeed.co.uk/billion-7800n

You don't give details of the line length from your exchange and I'm guessing you are on max 8Mbps ADSL in which case I certainly found that a Billion 7800n could achieve a stable sync speed of 7128Mbps with SNR set at 6. Anything below 6 was very likely to produce an inferior speed because of performance drop off in the evenings
Standard User zarkrax
(regular) Mon 20-Jul-15 16:58:21
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Re: ADSL Sync speeds getting slower


[re: 961a] [link to this post]
 
About 1.5miles away as the crow flies.

I always thought I was on ADSL 2+ because my upload speed is around 1028.

When I was on 3db target SNR The line would stay up to 1db at night but wasn't all the stable and either I would re-sync or it would re-sync. I then would leave it at the sync rate (Normally about 6700-6900) and the line would be ok.

Hopefully we are getting fibre installed by October, so didn't really want to buy any new kit if its not fibre compatible.
Does the billion work with fibre?

Edited by zarkrax (Mon 20-Jul-15 17:10:30)

Standard User 961a
(regular) Mon 20-Jul-15 20:03:09
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Re: ADSL Sync speeds getting slower


[re: zarkrax] [link to this post]
 
Personally I'd rather go stable at SNR 6 because in practical terms the actual speed achieved (rather than the sync speed) is probably little different

That billion doesn't work with fibre so it's probably not worth buying one if fibre is coming shortly
Standard User zarkrax
(regular) Tue 21-Jul-15 10:53:19
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Re: ADSL Sync speeds getting slower


[re: 961a] [link to this post]
 
I have looked at my download speeds over the course of the last year, and on a good day they were 6.3mbps (though usually it was morel like 5.5 - 6.0) now it's on 5.3, so lost a little bit on the top end. But as you all have said the line is way more stable now than it was (probably re-synced once a week before), and I have had it running 14 days on the new target SNR.

Thanks all for your help smile
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