ADSL- speed and distance..?

Assuming I have a superb nice shiney copper line..

What speeds are expected for the distances involved ?

Eg: at what distance can I get 512k, 1mb, 2mb, 4mb etc ?

Any ideas?

Doz

"Doz" <(E-Mail Removed)> wrote in message
news:xIUAd.346$(E-Mail Removed)...
> Assuming I have a superb nice shiney copper line..
>
> What speeds are expected for the distances involved ?
>
> Eg: at what distance can I get 512k, 1mb, 2mb, 4mb etc ?
>
> Any ideas?
>
> Doz
>
>
for an average line, under average conditions.
512k 7km +
1M 6km
2M 3-4km
4m maybe less than 3km.

its all to do with SNR rather than loss, however loss is a factor in SNR.

I have 1Meg at 6.4km, works solidly, but I live in the sticks, so less man
made noise around so SNR is workable. In the city, noise tends to be higher,
so range is reduced, but also in the city exchanges are nearer.

On Thu, 30 Dec 2004 15:18:09 -0000, "TheDragon" <(E-Mail Removed)>
wrote:

>
>"Doz" <(E-Mail Removed)> wrote in message
>news:xIUAd.346$(E-Mail Removed)...
>> Assuming I have a superb nice shiney copper line..
>>
>> What speeds are expected for the distances involved ?
>>
>> Eg: at what distance can I get 512k, 1mb, 2mb, 4mb etc ?
>>
>> Any ideas?
>>
>> Doz
>>
>>
>for an average line, under average conditions.
>512k 7km +
>1M 6km
>2M 3-4km
>4m maybe less than 3km.
>
>its all to do with SNR rather than loss, however loss is a factor in SNR.
>
>I have 1Meg at 6.4km, works solidly, but I live in the sticks, so less man
>made noise around so SNR is workable. In the city, noise tends to be higher,
>so range is reduced, but also in the city exchanges are nearer.
>
Is there a DIY method of measuring SNR?

No, only an ADSL modem capable of giving it (i.e. most, but NOT all) can
reveal an ADSL SNR. or a BT Whoosh test, both require an ADSL enabled line
to function.

Loss can be approximated on AVERAGE cables with an AVERAGE number of joints.
Roughlt 10dB per km. ie 6km is 60dB attenuation.

If you're at say 6.5m, is there a mid point speed as a matter of
interest?
ie 750k

Technically yes. However no ISP provides it.

You could in theory have any speed up to 8.192 meg down 768k up in steps of
64k.

"TheDragon" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)
> "Doz" <(E-Mail Removed)> wrote in message
> news:xIUAd.346$(E-Mail Removed)...
>> What speeds are expected for the distances involved ?
>>
>> Eg: at what distance can I get 512k, 1mb, 2mb, 4mb etc ?
>
> for an average line, under average conditions.
> 512k 7km +
> 1M 6km
> 2M 3-4km
> 4m maybe less than 3km.

Just worth pointing out that these "distance guideline" limits apply to BT
Wholesale provided ADSL.

LLU operators use their own line limits and hence difference "distances" -
for instance, virtually everyone who BT Wholesale is willing to giove a 2MB
connection too - could get 4MB on the same line from Bulldog/Easynet etc..

However, as has been said its really SNR which is important (as well as the
dB figure) - not the distance.

Regards
Sunil

"TheDragon" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>
> "Doz" <(E-Mail Removed)> wrote in message
> news:xIUAd.346$(E-Mail Removed)...
> > Assuming I have a superb nice shiney copper line..
> >
> > What speeds are expected for the distances involved ?
> >
> > Eg: at what distance can I get 512k, 1mb, 2mb, 4mb etc ?
> >
> > Any ideas?
> >
> > Doz
> >
> >
> for an average line, under average conditions.
> 512k 7km +
> 1M 6km
> 2M 3-4km
> 4m maybe less than 3km.
>
> its all to do with SNR rather than loss, however loss is a factor in SNR.
>
> I have 1Meg at 6.4km, works solidly, but I live in the sticks, so less man
> made noise around so SNR is workable. In the city, noise tends to be
higher,
> so range is reduced, but also in the city exchanges are nearer.
>
>


Dragon,

I am curious about which ISP provides you with a 1Mb service at over 6km
line length?

Wanadoo/BT will only provide me with 512kb at 6.2km and I appreciate that
line SNR may be my problem, though I also live out of town.

Also, are there any rumours about when BT may start to push 1Mb, in general,
over 6km?

Thanks

I was on 512k for over a year at this distance. So I knew the quality of the
line down to every quirk.

I used the steady SNR values (No mention of dB or length) when talking to a
technically minded broadband sales guy. I then insisted that with a SNR
Margin (0dB margin is the theoretical min that will sustain a link, approx
6dB SNR) of 21dB at 512, the change to 1 meg required approx 6 dB of extra
margin, so on 1 meg the estimated margin was 15dB. Still more than enough
ofr a steady connection. In fact a SNR Margin of 15 dB equates to an actual
SNR of 21dB as the margin sits at 6dB.

He said you obvioulsy done your home work, i then gave him number of my
business lines that are about 300 yards away and are capable of 2Meg
(Running at 1 Meg at present)on the BT database, again with all thier line
stats. He then compared them and agreed the database was wrong for my line,
and I could indeed have 1 Meg.
A week Later I got a call from one of the wholesale managers, she doesnt
want her number and name revealed, who authorised the connection and gave me
the activation date. Since then the line has never dropped due to lack of
signal. Currelt line stats from the router are below.
They indicate that my line will actually support 3 Meg downstream, ie there
are enough BIN's with a SNR margin of >0dB to provide 3 Meg of BW.
If your router can give this data, and you can get intouch with a technical
minded sales guy, there are a few, its all ammo to support your case.

Paul_Router> adsl status
--------------------------- ATU-R Info (annex
A) ----------------------------
Running Mode : G.DMT State : SHOWTIME
DS Actual Rate : 1152000 bps US Actual Rate : 288000
bps
DS maximum Rate : 3168000 bps US maximum Rate : 672000
bps
DS Path Mode : Fast US Path Mode :
Fast
NE Current Attenuation : 64.0 dB Cur SNR Margin : 13.0
dB
DS actual PSDM(C) : 00000007 US actual PSDM(R) : 0000231e
ADSL Firmware Version : 41e2be2c
-------------------------------- ATU-C
Info ---------------------------------
Far Current Attenuation : 31.5 dB Far SNR Margin : 15.0
dB
CO ITU Version[0] : 000f414c CO ITU Version[1] : 43420000
DSLAM CHIPSET VENDOR : < Alcatel >
-----------------------------------------------------------------------------
INTL, DSTREAM bytes/depth= 1, symbols/codewords = 0, latency=
0*0.25ms.
, USTREAM bytes/depth= 1, symbols/codewords = 0, latency=
0*0.25ms.
CODE, DSTREAM fast parity bytes= 0, fast codeword= 37.
DSTREAM intl parity bytes= 0, intl codeword= 0.
CODE, USTREAM fast parity bytes= 0, fast codeword= 10.
USTREAM intl parity bytes= 0, intl codeword= 0.
Setting>>
FDQ : Enable, TCM : Enable, EC : Disable, Framing Mode : 3.
Running>>
FDQ : In Use, TCM : In Use, EC : Off.
DS : Framing Mode 3, US : Framing Mode 3.
ADI ADSL Firmware Version: 41e2be2c
Paul_Router>

In article <(E-Mail Removed)>, TheDragon
<(E-Mail Removed)> writes
>I was on 512k for over a year at this distance. So I knew the quality of the
>line down to every quirk.

snip

>They indicate that my line will actually support 3 Meg downstream, ie there
>are enough BIN's with a SNR margin of >0dB to provide 3 Meg of BW.
>If your router can give this data, and you can get intouch with a technical
>minded sales guy, there are a few, its all ammo to support your case.
>

Trouble with SNR is that it may not be time stationary. Our line out
(from Berkeley to Sharpness) has a downstream attenuation of 56 to 58
db, depending on which modem we try, but the SNR has varied by more than
6db (from memory between 21 and 14 db - both 'working day figures' so
the night-time figures may be different again)
--
robert w hall