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Standard User jaybee2017
(newbie) Mon 24-Apr-17 13:59:33
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Re: How to make good a brain-dead FTTC service?


[re: MrSaffron] [link to this post]
 
Where does Ofcom say you are superfast? At 1.9km no-one should be under any idea that you are going to get superfast.

What do we say at https://labs.thinkbroadband.com/local/postcode-search


Sorry if I mislead here. Had no illusions about what to expect as the various online check services tended to be cautious, and would have been happy with 8-10Mb/s down. Instead and thanks to variable SNR & GINP are - in fact - getting in excess of 16Mb/s down. What I had not fully appreciated was how big a handicap a 1Mb/s upload channel would prove.

My point was that although improving matters somewhat for our at least a part of our village, the cabinet as positioned delivered "Superfast" to only a handful of properties (ref. https://checker.ofcom.org.uk/broadband-coverage for postcode EX16 9QD - the cabinet WWOAKF-2 is located at the fork in the road labelled "Stoodleighmoor").
Standard User jaybee2017
(newbie) Mon 24-Apr-17 14:07:34
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Re: How to make good a brain-dead FTTC service?


[re: David_W] [link to this post]
 
Though I don't know the history of your particular cabinet, it is very unlikely that Openreach deliberately chose a sub-optimal location for it. The cabinet will either have been sited at an existing PCP, or the network rearrangement needed to site the cabinet at a new PCP will have taken the topology of the existing cables into account. Network rearrangement is an expensive business and extensive rearrangement can soon eat up the available budget.


David_W - I think you are right about reason for the cabinet positioning. Moving it closer to our village would have necessitated extra cabling to "back haul" connections to a significant number of strung-out properties that - ironically - are too far off even now to consider using FTTC services.

A decision that was optimal for the OR accountants, not optimal for it's customers?
Administrator MrSaffron
(staff) Mon 24-Apr-17 14:11:04
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Re: How to make good a brain-dead FTTC service?


[re: jaybee2017] [link to this post]
 
Street view is not up to date, but you mean it is at this junction?

https://www.google.co.uk/maps/@50.9675726,-3.5415837...

Our guess was 150m out to the North West, and look ups will update to reflect this new position tonight.

If correct location then it is one of the most poorly located cabinets to date, but as its part of the CDS project, it is possible BT may have not wanted to do it, but local politics overrode them (e.g. got that nearby farm to get superfast), or if BT had got phase II contract they would have added an infill cabinet nearer to Kissing Gate Cross.

One contentious aspect of the CDS contract was the fate of those under 2 Mbps, so it may be that the cabinet location ticked that box sufficiently in the short term, and subsequent projects will fix that, but with no BT involvement in the next phase its talk to council and see what their plans are in terms of getting more people to superfast.

The BT involvement in Devon is not over, but unless the Openreach checker is talking of more work it is unlikely you will see anything more from BT.

The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.


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Standard User jaybee2017
(newbie) Mon 24-Apr-17 14:13:55
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Re: How to make good a brain-dead FTTC service?


[re: WWWombat] [link to this post]
 
There is a mechanism employed by the FTTC cabinets known as "upstream power backoff", UPBO. Its job is to reduce power on nearby modems, so that longer-range modems suffer less crosstalk, and get a better upstream speed.

However, the settings for this mechanism appear to be tunable by the operator, and can give different results to people at different distances. I cannot explain exactly how tuning works, but the upshot is that modems within (say) 200m get slower than expected upstream speeds, while those between (say) 200m and 900m get better, and then those beyond 900m get worse again. Instead of a 900m threshold, an operator could tune for a 600m threshold instead. Or a 1.2km threshold instead.

I have seen nothing (in, for example, the ANFP) where BT give details about their chosen setup for UPBO, and absolutely nothing that shows they can tune this setting for different cabinets. It suggests BT may have a single configuration common to all urban and rural cabinets.


WWWombat - thanks for that information. I'm a retired telecomms person (broadcast TV rather than telephone stuff) so will dig deeper using that information. (Sad to say I enjoy watching the modem stats as it juggles bit allocations to maintain data rates in the evening with the increase in MF radio station noise and the 2dB loss of SNR when our mystery interference source (sewage puping station?) comes on for a couple of hours.)
Standard User jaybee2017
(newbie) Mon 24-Apr-17 14:32:00
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Re: How to make good a brain-dead FTTC service?


[re: MrSaffron] [link to this post]
 
Street view is not up to date, but you mean it is at this junction?

https://www.google.co.uk/maps/@50.9675726,-3.5415837...

Our guess was 150m out to the North West, and look ups will update to reflect this new position tonight.


That's the spot - the wild flowers no longer grow so high thanks to two green cabinets and the OR mens' big boots. smile

If correct location then it is one of the most poorly located cabinets to date, but as its part of the CDS project, it is possible BT may have not wanted to do it, but local politics overrode them (e.g. got that nearby farm to get superfast), or if BT had got phase II contract they would have added an infill cabinet nearer to Kissing Gate Cross.


Kissing Gate would be an ideal location as it is fairly central to our rather linear village. At the moment the cable run goes to one end of the village (Quoit-at Cross) and then runs up through the village pretty well from one end to the other. Some of the properties forming the contiguous part of the village must be over 2.5km from the cabinets, as the cable runs.
Standard User Fastman2
(experienced) Mon 24-Apr-17 14:52:07
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Re: How to make good a brain-dead FTTC service?


[re: jaybee2017] [link to this post]
 
actually you would not have been able to backhaul those cables as that would have increased the line length and therefore worsened that ADSL -- that would not be allowed under the conditions of Licence that Openreach operates as you cannot worsen the ADSL service to force subscribers to but an FTTC service that's not equivalent
Standard User WWWombat
(knowledge is power) Mon 24-Apr-17 15:35:46
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Re: How to make good a brain-dead FTTC service?


[re: MrSaffron] [link to this post]
 
In reply to a post by MrSaffron:
Is that aspect not already covered possibly in the three power masks used? Short/Medium/Long with respect to avoiding undue crosstalk for ADSL2+ services.


Are you talking about the downstream power masks for VDSL2? The one where the ANFP shows 6 different masks (CAL=0, 10, 20, ... 50)?

If so, there are actually many more masks, for CAL=0dB through to CAL=52dB in steps of 2dB, varying by the distance of the cabinet from the exchange. 27 masks, in the lower portion of D1.

But the important bit is those are for downstream frequencies, not upstream. UPBO works across U1 and U2 instead, and varies by distance between CPE and cabinet.
Administrator MrSaffron
(staff) Mon 24-Apr-17 15:41:31
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Re: How to make good a brain-dead FTTC service?


[re: WWWombat] [link to this post]
 
Ta - not had time to read all the real techie docs for ages now

The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User jaybee2017
(newbie) Mon 24-Apr-17 16:06:42
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Re: How to make good a brain-dead FTTC service?


[re: Fastman2] [link to this post]
 
actually you would not have been able to backhaul those cables as that would have increased the line length and therefore worsened that ADSL -- that would not be allowed under the conditions of Licence that Openreach operates as you cannot worsen the ADSL service to force subscribers to but an FTTC service that's not equivalent

An interesting point that. Would there have been an obligation to connect the very long lines (with no hope of a VDSL2 service from that point) via the FTTC cabinet? If not the long lines could be left "as is", no back-haul needed, and the cabinet could have been better placed.
Administrator MrSaffron
(staff) Mon 24-Apr-17 16:12:48
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Re: How to make good a brain-dead FTTC service?


[re: jaybee2017] [link to this post]
 
Anything is possible given unlimited resources, but doing what you suggest would add to the costs.

If BT had the phase II cabinet I'd predict an infill cabinet in the future, but they don't for Devon so its down to the priorities of the council and what they direct the new contract holders to do (i.e. experience from elsewhere in the UK does not apply)

The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
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