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Standard User tehidyman
(regular) Tue 18-Sep-12 15:03:58
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Sky LLU speeds


[link to this post]
 
At present I am with IDnet on ADSL2+, Phone is with BT and TV - Sky. I am considering switching BB, and phone to Sky. I have identified the positives and negatives of switching the phone but am still uncertain about BB. My current noise margin is stable at 6dB, line attenuation 53.5dB and I sync at 4683kbps. Download speeds are just over 4.0Mb. My exchange is Sky LLU enabled but a check with Sky test indicates I may only get up to 2.0Mb. Can this be correct? I was expecting that LLU could be faster than current. Any comments appreciated
Standard User XRaySpeX
(eat-sleep-adslguide) Tue 18-Sep-12 15:16:47
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Re: Sky LLU speeds


[re: tehidyman] [link to this post]
 
In reply to a post by tehidyman:
I was expecting that LLU could be faster than current.
LLU is also ADSL2+ so you should get identical speeds, all things being equal.

I expect you are currently on 21CN WBC ADSL2+, but the BT IP Profiling on that is not divisive, so it won't be much diff when free of it smile

1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 16 Meg LLU => 2011: Orange 19 Meg WBC
Standard User RobertoS
(sensei) Tue 18-Sep-12 19:26:48
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Re: Sky LLU speeds


[re: XRaySpeX] [link to this post]
 
I believe the default Sky noise margin is 7dB as well, which won't help. The BT DLM should be dropping it to 3dB unless there is a lot of noise.

My broadband basic info/help site - www.robertos.me.uk
Domains,website and mail hosting - Tsohost. Connection - Plusnet Extra Fibre (FTTC). Sync ~ 56.0/13.9Mbps @ 600m.

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.


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Standard User RobertoS
(sensei) Tue 18-Sep-12 19:30:27
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Re: Sky LLU speeds


[re: tehidyman] [link to this post]
 
See my reply to XRaySpeX. Any chance you could post the line stats, then again straight after a reconnection well inside daylight hours please? Preferably using the test socket of the master for the second one, with just a filter and short ADSL cable to the router.

I'd hope to see a bit more than 4683kbps on that attenuation.

My broadband basic info/help site - www.robertos.me.uk
Domains,website and mail hosting - Tsohost. Connection - Plusnet Extra Fibre (FTTC). Sync ~ 56.0/13.9Mbps @ 600m.

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.
Administrator MrSaffron
(staff) Tue 18-Sep-12 19:40:18
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Re: Sky LLU speeds


[re: RobertoS] [link to this post]
 
Hope - if their line is one that can perform above the average that is.

Normal speed range at 53.5dB attenuation is 2700 Kbps to 4700 Kbps
Target Margin Estimate
9dB 3215
6dB 4693
3dB 6849

http://www.coolwebhome.co.uk/calc/calculator.php
So while it might be possible to go faster, its just worth doing the simple stuff, like check at test socket, before getting the hopes up too much.

Andrew Ferguson, andrew@thinkbroadband.com
www.thinkbroadband.com - formerly known as ADSLguide.org.uk
The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User RobertoS
(sensei) Tue 18-Sep-12 21:08:04
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Re: Sky LLU speeds


[re: MrSaffron] [link to this post]
 
I think I suggested exactly that check and more Andrew. And the word "hope" was specifically chosen. Not "expect". As for the "average", you know as well as I do that is based on readings including all the utterly lousily wired ones around. Plus I said "a bit", not "a lot".

I think you have a typo. Surely there is no way a drop from 6dB to 3dB adds 2150kbps? 1200kbps at best from my experience.

My broadband basic info/help site - www.robertos.me.uk
Domains,website and mail hosting - Tsohost. Connection - Plusnet Extra Fibre (FTTC). Sync ~ 56.0/13.9Mbps @ 600m.

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.

Edited by RobertoS (Tue 18-Sep-12 21:09:44)

Standard User XRaySpeX
(eat-sleep-adslguide) Tue 18-Sep-12 21:42:46
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Re: Sky LLU speeds


[re: RobertoS] [link to this post]
 
In reply to a post by RobertoS:
Surely there is no way a drop from 6dB to 3dB adds 2150kbps? 1200kbps at best from my experience.
I've had a gain of 3.7 Meg when dropped 3 dB.

From @ 6dB:
Connection Speed 16806 kbps 1208 kbps
Line Attenuation 26.5 db 14.4 db
Noise Margin 6.1 db 6.1 db
To @ 3dB:
Data Rate Information:
Stream Type Actual Data Rate
Upstream 1176 (Kbps.)
Downstream 20519 (Kbps.)

Defect/Failure Indication:
Operation Data Upstream Downstream
Noise Margin 6.3 dB 3.7 dB
Line Attenuation 12.9 dB 26.0 dB
both on Fast Path.

Admittedly it's at a higher level with diff routers and at the moment I'm only at 19.6 Meg @ 4.5dB:
Data Rate Information:
Stream Type Actual Data Rate
Upstream 871 (Kbps.)
Downstream 19571 (Kbps.)

Defect/Failure Indication:
Operation Data Upstream Downstream
Noise Margin 13.9 dB 4.4 dB
Line Attenuation 13.3 dB 26.5 dB
On my line I usually reckon on 1 Meg gain per 1 dB NM drop smile

1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 16 Meg LLU => 2011: Orange 19 Meg WBC

Edited by XRaySpeX (Tue 18-Sep-12 22:41:03)

Standard User RobertoS
(sensei) Tue 18-Sep-12 23:47:04
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Re: Sky LLU speeds


[re: XRaySpeX] [link to this post]
 
mmmm.

Can't argue with that. I hadn't thought about the effect on very high frequencies, that you have available on that attenuation.

My broadband basic info/help site - www.robertos.me.uk
Domains,website and mail hosting - Tsohost. Connection - Plusnet Extra Fibre (FTTC). Sync ~ 56.0/13.9Mbps @ 600m.

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.
Standard User ukhardy07
(experienced) Wed 19-Sep-12 00:12:10
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Re: Sky LLU speeds


[re: tehidyman] [link to this post]
 
It should be a similar speed. Perhaps a tad slower

Sky don't really have a target noise margin since DLM. It's more a target sync. The noise margin only comes into effect if the target sync would produce a sync below 7db

Even then DLM can now set a 3db SNR as the target.

DLM aims for a sync. E.g DLM may set a sync of 3000kbps. You would resync at 3000Kbps whenever the router rebooted. Even if this gave an SNR of 10db.

If the sync at 3000Kbps would give an SNR below 7db, then it syncs slightly slower but this is unlikely with Sky.

Edited by ukhardy07 (Wed 19-Sep-12 00:15:48)

Standard User Ignitionnet
(knowledge is power) Wed 19-Sep-12 01:26:29
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Re: Sky LLU speeds


[re: tehidyman] [link to this post]
 
Extremely likely to go down. Sky's line management is geared more towards saving Sky money powering lines than getting maximum performance out of your line.

There's a good reason why Sky don't quote speeds on their website any more.

ADSL Link
Downstream Upstream
Connection Speed 16379 kbps 1101 kbps
Line Attenuation 17.0 dB 11.4 dB
Noise Margin 6.0 dB 8.5 dB

They pick a speed for your line during the first few days then they drop the transmit power on their side so that you achieve that speed and no higher and they save a few pennies powering your line to maximum to push it to its best.

This feature is sold as improving the stability of the service.
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