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Standard User MaddogBattie
(fountain of knowledge) Tue 05-Feb-13 22:10:47
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FTTC enabled but line too long....


[link to this post]
 
My cabinet got enabled last month (yay!) but I can't order FTTC as my line turns out to be too long to the cabinet and BT don't think it will make 5Mb/s (I has a sad..)

Is there anything that can be done?

I live in a small village in Cornwall (Callestick - TR4 9LN) which is 2km as the crow flies from the cabinet (P13 - Perranporth Exchange). Unfortunately, the actual cable distance to the cabinet is 5km apparently so most people in the village can't order FTTC due to the predicted speed being less than 5Mb/s. Interestingly one house in the middle of the village can order with a predicted speed of 6.5Mb/s. I've no idea why they are special.

Current speeds for people in the village are 2 to 4Mb/s so it is likely that most people will get above 5Mb/s if allowed to order as at least 2.5km (cabinet - exchange) will be removed from the line length.

Is there anyway of either being allowed to order even with our horrible line length? I'm guessing getting BT to reroute the cable more sensibly is unlikely to ever happen. The ideal solution would be a new cabinet in the village but I guess that too is dreamland.
Administrator MrSaffron
(staff) Tue 05-Feb-13 22:15:11
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Re: FTTC enabled but line too long....


[re: MaddogBattie] [link to this post]
 
Given we have seen perhaps one person with a 3km long line getting just 1 to 2 Meg if I recall the chances of you getting anything useful is unlikely.

Alas the frequency plans for VDSL in the UK mean it can perform worse than ADSL, which due to its lower frequencies has a better range.

At this point the best bet is to get the person who can get 6.5 Mbps to order and see what they get in reality.

Andrew Ferguson, [email protected]
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 05-Feb-13 22:26:21
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Re: FTTC enabled but line too long....


[re: MaddogBattie] [link to this post]
 
Has the fast house only just had the phone line installed. As in during the last 3 days?

My broadband basic info/help site - www.robertos.me.uk | Domains,website and mail hosting - Tsohost.
Connection - Plusnet UnLim Fibre (FTTC). Sync ~ 54.3/15.4Mbps @ 600m. - BQM

"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 MaddogBattie
(fountain of knowledge) Tue 05-Feb-13 22:32:54
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Re: FTTC enabled but line too long....


[re: RobertoS] [link to this post]
 
No, it has been installed for a long time.
Standard User RobertoS
(sensei) Tue 05-Feb-13 22:35:36
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Re: FTTC enabled but line too long....


[re: MaddogBattie] [link to this post]
 
Odd then.

And damned annoying for you and the rest!

My broadband basic info/help site - www.robertos.me.uk | Domains,website and mail hosting - Tsohost.
Connection - Plusnet UnLim Fibre (FTTC). Sync ~ 54.3/15.4Mbps @ 600m. - BQM

"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 MaddogBattie
(fountain of knowledge) Tue 05-Feb-13 22:44:50
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Re: FTTC enabled but line too long....


[re: MrSaffron] [link to this post]
 
That isn't good news.

I didn't realise VDSL didn't use the lower frequencies. I thought it just used additional higher ones. Oh well.

Any other magic ideas on what we can do? On demand FTTP is going to be too expensive individually being that it is 2km to the cabinet but there is the potential of fibre being brought into the village then shared. Is this something likely to be offered?

We will see what happens with the house that can order. They have a bit of dosh so I doubt that cost is an issue for them.
Standard User MaddogBattie
(fountain of knowledge) Tue 05-Feb-13 22:48:54
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Re: FTTC enabled but line too long....


[re: RobertoS] [link to this post]
 
Not as bad as being 2km from the cabinet but having a 5km line. That was rather depressing to find out as I knew then we weren't ever going to get fantastic speeds.

As FTTC has been enabled it also means we are unlikely to get FTTP now either. Lets hope some of the other options for fast broadband get tried out on our village. We can but hope.
Standard User Chrysalis
(eat-sleep-adslguide) Tue 05-Feb-13 23:59:11
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Re: FTTC enabled but line too long....


[re: MrSaffron] [link to this post]
 
its more that the power cutback on vdsl (to protect adsl) makes vdsl worse on longer lines.

If a vdsl line can only use the adsl frequencies then it will be crippled as it has limited power on those frequencies, so then adsl works better, but of course adsl may be on a longer distance due to been from the exchange instead of the cabinet.

It seems when a cabinet is close to the exchange the power cutback isnt that severe and on frequencies above the adsl1 range, but when its far from the exchange (like mine) the power cutback almost completely wipes out the low frequencies. When I compare bitloading graphs posted from unlocked hg users (most who seem to be on cabinets close to exchanges) my estimate is about 8mbit/sec of attainable sync difference depending on which power masking you on.

BT Infinity 2 Since Dec 2012 - Estimate 65.9/20 - Attainable peak 110/36 - Current Sync 71/20

Edited by Chrysalis (Wed 06-Feb-13 00:00:21)

Standard User Zarjaz
(knowledge is power) Wed 06-Feb-13 00:12:03
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Re: FTTC enabled but line too long....


[re: MaddogBattie] [link to this post]
 
On demand FTTP is going to be too expensive individually being that it is 2km to the cabinet but there is the potential of fibre being brought into the village then shared. Is this something likely to be offered?

It won't be offered, but what about a few houses very nearby clubbing together to get one home enabled, and then share it out ? 330000Kbps could be shared around a fair bit ?

Standard User Ignitionnet
(knowledge is power) Wed 06-Feb-13 09:34:38
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Re: FTTC enabled but line too long....


[re: Zarjaz] [link to this post]
 
In reply to a post by Zarjaz:
It won't be offered, but what about a few houses very nearby clubbing together to get one home enabled, and then share it out ? 330000Kbps could be shared around a fair bit ?


If you an find an SP actually offering that outside of trials.
Standard User ferretuk
(regular) Wed 06-Feb-13 11:55:19
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Re: FTTC enabled but line too long....


[re: Zarjaz] [link to this post]
 
It would be far cheaper to buy a few satellite broadband connections and share those instead...
Standard User yarwell
(sensei) Wed 06-Feb-13 12:17:49
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Re: FTTC enabled but line too long....


[re: Chrysalis] [link to this post]
 
the power masking requires that the injected power is the same as that of exchange based services arriving at the cabinet, unless the frequency band is unuseable from the exchange in which case the FTTC can "re-use" the frequency at full power.

So a cabinet a long way from the exchange should have a good range of frequencies at decent power levels, good for long lines, but one close to the exchange is as you say hampered.

I do wonder if these things get setup correctly though.

--

Phil

MaxDSL - goes as fast as it can and doesn't read the line checker first.

MaxDSL diagnostics
Standard User Chrysalis
(eat-sleep-adslguide) Wed 06-Feb-13 12:51:40
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Re: FTTC enabled but line too long....


[re: yarwell] [link to this post]
 
well I am just guessing based on bitloading graphs.

Exchange based services have a lesser impact and achieve higher bitloading on the affected tones, and consider also that those tones are weaker (tones above 250 weaker than below) then it looks to me that there is a higher penalty when the cabinet is further away.

This may well be deliberate because long adsl lines may need more help from vdsl power cutback to stay working than short adsl lines.

BT Infinity 2 Since Dec 2012 - Estimate 65.9/20 - Attainable peak 110/36 - Current Sync 71/20
Standard User Michael_Chare
(committed) Wed 06-Feb-13 14:56:37
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Re: FTTC enabled but line too long....


[re: MaddogBattie] [link to this post]
 
In reply to a post by MaddogBattie:
Any other magic ideas on what we can do? On demand FTTP is going to be too expensive individually being that it is 2km to the cabinet but there is the potential of fibre being brought into the village then shared. Is this something likely to be offered?

It would be interesting to see how much BT would charge for installing FTTP.

You could ask Gigaclear just what they would need for a viable project. Where I live Gigaclear want 190 commitments (30%) over quite a spread out area.

Michael Chare
Standard User yarwell
(sensei) Wed 06-Feb-13 14:57:53
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Re: FTTC enabled but line too long....


[re: Chrysalis] [link to this post]
 
I think it's a curve, if the cabinet is a very long way from the exchange there isn't much of a constraint on FTTC injection at all. As you get closer the FTTC has to back off to the same level of signal at the PCP as the exchange achieves (approx) and hence is more compromised.

So if you have a long line to the cabinet it's best if the cabinet is also a long way from the exchange. In fact in general there's more tones & power available on distant cabs, the benefit is not just to the long lines from the cab.

--

Phil

MaxDSL - goes as fast as it can and doesn't read the line checker first.

MaxDSL diagnostics
Standard User Ignitionnet
(knowledge is power) Wed 06-Feb-13 18:32:22
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Re: FTTC enabled but line too long....


[re: ferretuk] [link to this post]
 
In reply to a post by ferretuk:
It would be far cheaper to buy a few satellite broadband connections and share those instead...


They'd all need to be unlimited. The ongoing costs would soon catch up with the heavy initial cost of an FTTPoD solution.
Standard User Lorian
(committed) Thu 07-Feb-13 08:38:09
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Re: FTTC enabled but line too long....


[re: yarwell] [link to this post]
 
My cab is a long way from the exchange and I'm quite a long way from the cab. Power back-out blows a very obvious whole in the lower frequencies and heavily effects my transmit speed. The bit loading reflects the PBO mask, which isn't a straight forward curve.

The power back-out masks are published somewhere, I can find them if need be, but they definitely effect users in the "long long" category as the power is backed out to avoid interference with ADSL on the long d-sides.

IIRC there are 5 different masks that are applied to long d-sides, and which mask is applied is dependant on the electrical length of the cabling from the cab to the exchange, the further it is the more the attenuation applied.

Or something like that smile

Edited by Lorian (Thu 07-Feb-13 08:43:02)

Standard User yarwell
(sensei) Thu 07-Feb-13 09:28:03
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Re: FTTC enabled but line too long....


[re: Lorian] [link to this post]
 
indeed, I have the graphs. The five illustrated masks are just examples from the provided calculation procedure.

With a 50 dB loss at 300 kHz from exchange to cabinet there is no penalty at 550 kHz and above compared to any other cabinet location. With only a 20 dB loss from exchange to cabinet there is a penalty up to over 2 MHz, so the 50 dB cab can put out more power between 550 kHz and 2MHz but less below 550 hence my speculation that it may be better to be on a distant cabinet.

--

Phil

MaxDSL - goes as fast as it can and doesn't read the line checker first.

MaxDSL diagnostics
Standard User Chrysalis
(eat-sleep-adslguide) Thu 07-Feb-13 09:38:10
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Re: FTTC enabled but line too long....


[re: yarwell] [link to this post]
 
yes but the shorter E sides have no penalty below 250 whilst the long E sides do.

The penalties applied to short E sides seem less severe (higher bit loading), this combined with the fact they get full power on the valuable 0-250 range.

BT Infinity 2 Since Dec 2012 - Estimate 65.9/20 - Attainable peak 110/36 - Current Sync 71/20

Edited by Chrysalis (Thu 07-Feb-13 09:38:29)

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