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[graevine1]

You are correct Roseway, however there are two routers that do not have the restriction and its not noted the names of the two from early last year which do have a greater count. I must dig it out as knowing the names may be useful so we can establish the true line loss. However dare I say how far in cable length is he from the exchange. then dare I say 10db/kilometer line attenuation.. Have a great day

[mr_chris]

> However dare I say how far in cable length is he from the exchange. then dare I say 10db/kilometer line attenuation

Graevine, you can dare to say whatever you want - but even if the line worked out at say 15dB/km loss, that wouldn't give us any more clue as to the source of the dropouts. Without wishing to disrupt this thread too much, I would like to take this up with you once more - namely the old 10dB/km chestnut.

I remember that a lot of people were saying this figure could be used as a very rough guestimate of the length of your line, when ADSL was first available in the UK - when perhaps a handful of people on each exchange had 512k/288k speeds - almost no crosstalk, BT would only install on good quality lines whose line attenuation figure did not exceed 45dB.

I would urge you to read this page which I have found on the Whirlpool forums in Australia, which, obviously whilst I cannot 100% prove its correctness, makes perfect sense to me as to why this 10dB/km is a practically unachievable level nowadays on a DSL Max line.

I have quoted the relevant part from the page:

In an ADSL meaning there are two separate and distinct versions. SIGNAL attenuation is what's reported for a current connection (e.g. from your modem) and an average of each individual bucket in the connection, it changes continuously. LINE attenuation is what's reported from a line SQ (Service Qualification) and is measured at a set frequency and signal strength by your providers DSLAM, it can be used to make speed guesstimations and is a good indicator of line health.

To clarify,
LINE attenuation (reported by DSLAM) is about wire health
SIGNAL attenuation (reported by modem) is about connection health and is only useful when considered with SNR margins, power levels and connection speed.

So basically, if this page is correct, the 'attenuation' figure reported by the router is simply an average of each individual bit bucket.

This would account for many factors:

1. Why different routers report different attenuation - different routers load the buckets differently - especially if there is spare space, some will spread the load out and some will load them from the bottom first, filling each bucket before moving onto the next one.

2. Why attenuation can rise very slightly when moving from fixed line to a Max line. My attenuation rose by a small amount (about 0.3-0.5dB) each time I got an upgrade from 512k to 1Mb to 2Mb, then to Max. On ADSL2+, my attenuation rose by a further 4dB, which accounts for the poorer quality of the signal at the much higher frequencies used by this technology.

It's a nice theory, not least of which it would explain both why you are saying loop loss should be 10dB/km (old information?) and we're saying that now appears to be an unrealistic goal!!

[graevine1]

Hi, I do gererally agree with that pretty excelent piece on Whirlpool, it is quite well structured in almost plain English. Great analagy toooooo.

The inf and I quote "LINE attenuation (reported by DSLAM) is about wire health
SIGNAL attenuation (reported by modem) is about connection health and is only useful when considered with SNR margins, power levels and connection speed.

There's a bit of a twist with attenuation, it increases with frequency; the higher the frequency the higher the attenuation"

THE IMPORTANT FACT IS, I have always stated when I have published, or reported that the figures obtained from routers are only an excelent guide, and rarly to far away from INDICATING line condition, and cannot be taken in the same way that a certified test, by certified test equipment operated by suitably trained and qualified Engineer/Scientist can be recorded. A cable or individual twisted pair test whether at DC or 100MHz if it indicates an abnormal attenuation from the figures expected for that cable, indicate that corrective action should be considered and if not immediatly performed should result in compensation to the customer connected to that pair. We have seen in the recent OFCOM release that they are intending it would appear to acquire teapots fabricated from a better quality of chocolate!!!

[kitz]

then dare I say 10db/kilometer line attenuation.. Have a great day

and you have been previously warned about bringing that up when it has no relevance to the OPs post since it only serves taking the thread off-topic and detracts from actually helping someone who comes here for assistance. 1. 2. 3. 4.

As chris eloquantly put it
"even if the line worked out at say 15dB/km loss, that wouldn't give us any more clue as to the source of the dropouts."

Youve done it again in a thread where it bears no relevance to finding a solution for the OP.
If its relevant fine then feel free to mention it...  but if it isnt please dont... 
but since you have, its about time I responded to your comments.

There's a bit of a twist with attenuation, it increases with frequency; the higher the frequency the higher the attenuation

Exactly!
A fact that I have previously stated, but graevine chose to ignore simply because it was me who said it... preferring to responded with the insults such as "pretend competent engineers" sadly misleading those seeking advice".
Ive also said that any old reports that anyone may have based for voice is wrong. Whilst there may be standards laid down for voice, there is nothing for adsl.

Instead he relished that Phil came out with some figures and chose to focus on those, not realising that phil had made a error and done the calculations wrong.
Someone was so focused on a self ego trip and attacking me to completely overlook the mistake in Phils post that I immediately spotted.  Unfortunately the thread was locked due to offensive remarks before I got to read the post, therefore I wasn't able to respond to it.

Hopefully though anyone reading that thread will also spot the obvious error.
Just because I don't work in the industry doesn't make me stupid..  nor does it give anyone the right to diss me or the site simply because Im not a trained telecom engineer. 
Its not me thats claiming Im an expert in this field, unlike some I could mention who are implying that they are.

My attenuation rose by a small amount (about 0.3-0.5dB) each time I got an upgrade from 512k to 1Mb to 2Mb

On average attenuation is said to increase by 1dB for each 4Mb of speed increase, as it utilises more of the higher frequency bins.
ADSL2+ uses higher output power, doubles the downstream bits and has an increased frequency spectrum which on average increases the atten in the region of 3-4dB.

different routers load the buckets differently - especially if there is spare space, some will spread the load out and some will load them from the bottom first, filling each bucket before moving onto the next one.

makes sense.

have always stated when I have published, or reported that the figures obtained from routers are only an /snip/ guide,

Ahhh glad that's sorted now, I'm pretty sure I told you at the beginning of the year, that you cant always rely on router stats for the attenuation, simply because different routers will report different figures. 
Which incidentally is something afaik I was one of the first to bring up on AG many years ago in the early days of adsl..  I certainly know that post was referred to by others for quite a while.

[jabns]

Just to back that up my two Sangoma S517 PCI modems report different attenuations by 3DB on all my lines.

EDIT: Probably best to move the last 5 posts(inc mine) to the tech chat section AGAIN as not to confuse the OP. I don't know what he gets out of ruining threads  .

[kitz]

@ graevine1

Actually I've decided Im going to split this from the original post. 
Theres too many threads that have already gone off topic with this debate and it totally detracts from the OPs question.
which is what you've been asked not to do in the past.

I'm sick and tired of having to apologise for other peoples behaviour over the past six weeks that I don't see why I should have to apologise once again for your behaviour.  I'm fully aware of the downright lies and nasty rumours you have been spreading over the past few weeks - Enough people have told me.

So I'm not a trained BT engineer, what the hell does that have to do with it?

Without belittling any CS support staff, you can bet your bottom dollar that I have far more qualifications in computing than the vast majority of them do.  I think its pretty fair to say that I know way more about adsl than most of them do.
And Yes I damn well could work in the industry if I wanted to.
What you perhaps dont know is that my history with adsl goes back many years and Ive often been one of the first to disclose adsl information to the general public.   Ive even disclosed information to AG... and written long posts and articles on there and for other sites way before your time.

You have dissed this site once too often, you have no idea of the vast experience and knowledge of some of the regulars who frequent here, and just because they arent BT related staff doesn't mean anything less.  Some of the regs here are people who have written "how too's for AG" in the past.

But you see its not us that are falsely proclaiming to be an expert in the field.  I certainly haven't...  unlike you.
I don't get my kicks out of trying to make out I'm something I'm not, I don't go around spreading lies in PMs.

I find it sad that you don't get what this site is all about - its about imparting knowledge and trying to help other people.
Its certainly not about massaging someone's ego and dirty snide tricks behind someone's back.  Its not about one-upmanship and "Im better than you" attitudes either.   

Its all about sharing what knowledge each of us has and bringing it to a level that the General Public can understand.
If you don't get that then you really are one sad individual and not welcome here.