Very low SNR, how to convince BT to check?

Hi, I've had BT Infinity for a couple of years now.. Only getting 35 Mbps at the moment which I've always thought strange because I'm on a residential street not far from the exchange, so I guess it must be the quality of the copper between me and the cabinet. I'm sure I should be able to get the full 70 Mbps

I'm now using a Draytek 2860 which allows me to check line stats and I'm seeing 6 dB SNR which I believe is borderline.

Does anyone have any method for convincing BT to commit an engineer to come out and test the cable between my property and the cabinet?

6dB noise margin is the standard value on FTTC. As you are close to the exchange it's possible you used to get nearly 24Mbps on ADSL2+ with a high noise margin, but FTTC and ADSL2+ don't work the same way in that respect.

Please could you also supply the rest of the stats, the exchange name, and your cabinet number.

The estimates from this checker would be useful. (Just copy and paste, we don't need the pretty layout using a screen print). Also on the line above the table, is the cabinet number what you expect?

Could you also run the BT Wholesale Performance Test, ignoring all the red instructions for now, and at the bottom of the results page click the Further diagnostics button. Give it your phone number when asked, then copy and paste the contents of both the down boxes of results . We don't need the fancy graphics.

Edited by RobertoS (Sat 26-Sep-15 23:54:24)

Roberto, thanks very much for the advice. Here's my detail:

From the "Availability Checker"

Telephone Number 0118xxxxxx on Exchange CAVERSHAM is served by Cabinet 6
Featured Products

Downstream Line Rate(Mbps)
Upstream Line Rate(Mbps)
Downstream Range(Mbps)
Availability Date

High Low High Low
FTTC Range A (Clean) 35 26.8 7.5 5.5 -- Available
FTTC Range B (Impacted) 28.1 15 7.2 3.3 -- Available
WBC ADSL 2+ Up to 12 -- 7 to 17 Available
WBC ADSL 2+ Annex M Up to 12 Up to 1 7 to 17 Available
ADSL Max Up to 6.5 -- 5.5 to 8 Available
WBC Fixed Rate 2 -- -- Available
Fixed Rate 2 -- -- Available
Other Offerings
FTTP on Demand 330 30 -- Available
Fibre Multicast -- -- -- Available
Copper Multicast -- -- -- Available

From the BT Wholesale Broadband Performance Test:

Download Speed (Mbps): 33.09
Upload Speed (Mbps): 5.68
Ping Latency (ms): 25.88

From my router:

DSL Connected : Down Stream : 34998Kbps / Up Stream : 6220Kbps
Running Mode: 17A
Actual Rate: 34998/6220, Attainable: 37229/6250
Path Mode: Fast
Interleave Depth: 1
Actual PSD: 6.9 dB (Downstream) / 11.2 dB (Upstream)
SNR Margin: 7 dB (Downstream) / 6 dB (Upstream)
Attenuation: 25 dB (Downstream) / 29 dB (Upstream)
CRC: 181 (Downstream) / 14627 (Upstream)
FECS: 0 (Downstream) / 257709 (Upstream)
ES: 52 (Downstream) / 12573 (Upstream)
UAS: 25 (Downstream) / 317 (Upstream)
...

So your line is running right at the top of the BT estimations and BT would never consider sending an engineer unless your sync was to drop below 26000Kb/s or 26Mb/s.

Fibre (FTTC) is based on the distance from the cabinet and not the exchange and uses significantly higher frequencies that ADSL meaning that they decline in quality much quicker the further they have to travel from the cabinet.

The SNR of 6db is standard for fibre connections and will only ever be higher if a person is so close to the cab that they are able to achieve higher speeds than the package they purchase can allow.

Cabinet 6 is at https://www.google.co.uk/maps/@51.4713133,-0.9781026...

So the next question is how far is the original poster from that location.

Does that matter... BT Wholesale and Openreach have final say and that will be that the estimates are XY&Z

Yes it does matter, because if they are at about the right distance for the attenuation, then safe to say nothing more to be got from the line.

The title of this post is "How to convince BT to check" and based on the BT's own estimates, they certainly wouldn't consider checking anything... you know that as well as I do!

The only thing that can come from bringing up distances and attenuation figures is frustrations as and example they may be much closer to the cab but there line may route via another dimension (exaggeration)

So explaining the reality of being say 700m from a cabinet to an end user who otherwise may think that much higher speeds are possible at that distance is not worth doing?

not really as it could open up a whole can of worms!

Say you said that too me with 55meg but then you tell me I'm 200-250 metres from the cab so should get close to full 76Mbps, but then turns out you measured my line going an alternative route 350 metres, thats still then leave's me looking up speeds vs distance and finding I should still get 70-80meg...

then it opens up the reasons to why my line is under performing?

I know the above might be a bit long winded but it has a point.

Okay so to save myself future time no more helping people with cabinet locations and distance estimates I guess.

Suppose you could do that but there's no need to get agitated about something that was never required in the first place.

If the OP came back and asked why speeds where estimated as they where then fair enough but now all they have ended up with is lodes of information to digest that may lead them to get annoyed and be further disappointed with the service they have had for a few years.

Hey, MrSaffron, please don't.

I don't get the speed from FTTC I had hoped for but in reality it makes little difference really. It's still much better than ADSL2+.

The TBB forum would be sadly compromised without your effort, just my opinion..

First thing to do is to make sure of your facts ... know all of your stats, know the distances from cabinet to house - direct straight line AND an approximation of the route the cable takes. Ask here for a sanity check on the stats, location and distance.

I think that's the first live FTTC cabinet I've seen on Google maps, and it's a 2012 picture.

As you say, what we now need to know is where that is in relation to the OP.

Sorry but why do we need to know this?

The question...

In reply to a post by philask:

Hi, I've had BT Infinity for a couple of years now.. Only getting 35 Mbps at the moment which I've always thought strange because I'm on a residential street not far from the exchange, so I guess it must be the quality of the copper between me and the cabinet. I'm sure I should be able to get the full 70 Mbps

I'm now using a Draytek 2860 which allows me to check line stats and I'm seeing 6 dB SNR which I believe is borderline.

Does anyone have any method for convincing BT to commit an engineer to come out and test the cable between my property and the cabinet?

Was answered with the line is fine, the SNR is on target and the line is performing to its estimates and BT will not be convinced to do anything with it.

why now are we on Google Street View mooching at a cabinet and asking for details to guess where the cable goes... everyone seems to making a big issue out of nothing.

You seem to be making one heck of a fuss in this thread, on completely specious grounds in both instances. Why do you need to object to my posts when all yours have been ridiculous?

Please note you are the one who hasn't helped the OP in any way. Andrew and myself both have.

Ahem...

In reply to a post by mlmclaren:

So your line is running right at the top of the BT estimations and BT would never consider sending an engineer unless your sync was to drop below 26000Kb/s or 26Mb/s.

Fibre (FTTC) is based on the distance from the cabinet and not the exchange and uses significantly higher frequencies that ADSL meaning that they decline in quality much quicker the further they have to travel from the cabinet.

The SNR of 6db is standard for fibre connections and will only ever be higher if a person is so close to the cab that they are able to achieve higher speeds than the package they purchase can allow.

All Andrew has done is post a link showing the OP there cabinet and then asked for information that is irrelevant to the original question, you asked the OP to provide information which I picked up the reply from the OP this morning and then confirmed their line looks fine and matches the BT estimates..

So I would like too know what I have done wrong and why me trying to avoid any confusion for the OP has lead to defamatory allegations being made against myself.

Well, for one thing what you quote here from your earlier post is incorrect.

Edited by RobertoS (Sun 27-Sep-15 19:23:37)

care to elaborate?

No. At least two errors of fact though.

No? Two? Rubbish!

Now thats helpful!

Edited by mlmclaren (Sun 27-Sep-15 19:42:17)

Children, children, be nice now!

"He Started It"

Yikes, I think I lit a fire! Sorry guys...

Anyway if that's cabinet 6 then it's plenty far away from me..

As the crow flies: 700m

Roughly following the street to that location: 880m

(PS. despite the bickering, thanks to everyone who's trying to help)

My apologies

In reply to a post by philask:

Yikes, I think I lit a fire! Sorry guys...

Anyway if that's cabinet 6 then it's plenty far away from me..

As the crow flies: 700m

Roughly following the street to that location: 880m

(PS. despite the bickering, thanks to everyone who's trying to help)

In that case, your line is good and performing within expectations.

There should be an ordinary phone cabinet within 50-60 metres of it - probably much closer to it than that. May be across a road or round a corner. Pictures of various cabinets.

The FTTC cab itself will not have a number on, but the phone cabinet (PCP) should have it.

As a point of interest, what connection speed did you have on ADSLx?

Edited by RobertoS (Sun 27-Sep-15 21:39:25)

A cab I know well, quite a lot of aluminium in the ground round that way.

Ok so stupid question possibly but I'm sure there's a FTTC cabinet closer to me than that, is it possible I'm connected to that cabinet simply because that's historically where my line is routed? Is there any way I can convince / pay to have my line moved to a nearer FTTC cabinet? (I'm near the corner of Kidmore Road and Richmond Road).

Is there any way I can convince / pay to have my line moved to a nearer FTTC cabinet? (I'm near the corner of Kidmore Road and Richmond Road).

Oh you can always pay to get what you want, but I suspect the final cost and hassle involved would make it vastly expensive.

Surely if you are on the junction of Kidmore/Richmond your line is fed from Cab 9 ?

In reply to a post by Zarjaz:

Is there any way I can convince / pay to have my line moved to a nearer FTTC cabinet? (I'm near the corner of Kidmore Road and Richmond Road).

Oh you can always pay to get what you want, but I suspect the final cost and hassle involved would make it vastly expensive.

Surely if you are on the junction of Kidmore/Richmond your line is fed from Cab 9 ?

An earlier post give the DSL Checker results which say Cab6.

An earlier post give the DSL Checker results which say Cab6.

Yep I saw that, but as you can see from his post and my link his description of his address puts him exactly by cab 9.
AFAIK all those properties in that vicinity are fed off of 9.







As an aside, I passed a new merc with an MHC5 numberplate this weekend, have you been splashing out ?

Isn't 25dB attenuation a bit high if so, even with aluminium around?

Yep, agreed.

In reply to a post by Zarjaz:

An earlier post give the DSL Checker results which say Cab6.

Yep I saw that, but as you can see from his post and my link his description of his address puts him exactly by cab 9.
AFAIK all those properties in that vicinity are fed off of 9.

You will be round there doing a few checks!

In reply to a post by Zarjaz:

As an aside, I passed a new merc with an MHC5 numberplate this weekend, have you been splashing out ?

No ... I prefer MHC 1760

Yeah exactly, Cab 9 is just two doors away from me.. no idea why we're connected to Cab 6... Don't suppose there's an easy way to change cabinets?

Don't suppose there's an easy way to change cabinets?

No there isn't I'm afraid.

Cab 9 is just two doors away from me.. no idea why we're connected to Cab 6..

I'm hugely surprised by that too, are you on the same side as the cab ? I know for sure that all the stuff going up the hill from cab 9 is fed off of cab 9.

You will be round there doing a few checks!

Nah, still off work at the mo [glum]

No, opposite side and one of the first houses on the street.. Obviously we were connected before Cab 9 was even installed... [censored] annoying I'm sure we'd get the full 76 Mb/s if we were connected to 9.

I wonder if I had a second line installed and the FTTC moved to that... bah!

I wonder if I had a second line installed and the FTTC moved to that... bah!

Nope, that would still be fed off of the same DP (pole in your case) that the first line is fed by.

As I mentioned before, IF you could find an SP who would place a bespoke order for a line fed off of cab 9 ..... and that really is a HUGE ask, thats the only way. Think LOTS of money.

You could do a straight swap, your place for my place in Woodley, I get the full Kahuna sync wise.

Do you have a neighbour who is on cab 9?

Perhaps "they" could have a second line installed and you could come to some arrangement.

My grand-daughter is in a similar situation.

Her PCP cabinet and the FTTC are about 1,000 Metres away, combination of the PCP location, the u/g line goes beyond her house to a pole.

From that first pole, the overhead comes back on the other side of her house, to a pole beyond it, ie almost as though it was going back to "her" PCP but does encounter a second pole, then eventually "forward" to her house.

There is a newer PCP and its FTTC, probably about 300 M in a straight line from her house, say 500 M if the most obvious u/g route was used.

Her house is a recent build on the location of one of a distinctly older group of houses.

The newer PCP was added to cover a "new small estate", replacing elderly cottages.