11 km line, stable 512kb connection. 1Mb seem possible.

A good example of how a long line isolated from interference has very
negligible effects on the availability of broadband.

We are in the North York Moors national park, at LEAST 11km from the
exchange; I think it is very likely to be in the region of 12-14km.
There are about four street lights along the entire length of the line
and no other obvious sources of interference, which is obviously
significant.

The 1 mile stretch of line to our house was installed about 10 years
ago and the rest of the line is obviously rather ancient, so probably
none of the thinner 0.5mm copper cable, which I think has been used in
the recent past, and it is safe to assume no aluminum or steel cable
either.

Obviously, I got a "very unlikely" result for any and all ADSL
services on the BT broadband checker on the basis of the length of the
line.

I ordered the day ADSL was installed at the exchange and the router
synced (at 576000) on the fourth working day, three days ahead of the
scheduled activation date. Few minutes after I tried to login for the
first time the Plus Net account was automatically activated, as
advertised. Superb service so far, certainly recommend them.

Anyway, I'm running a Vigor 2600G connected direct to the main box
via the ADSL faceplate from Clarity:

SNR is typically 24.5 to 26, often holds steady at 25.

Loop/line attenuation is typically 60. Sometimes it drops to 58.5,
occasionally it peaks at 61. Never any worse than this, thankfully, so
I think 1mb may be doable when/if BT upgrade the exchange, as it is
mostly at or below the 60db BT limit.

I don't think I have upstream figures on the Vigor but a totally
stable connection and both upload and download speeds are superb.

The minor fluctuations in signal/noise margin and attenuation may be
due to local factors. We're not on the national grid so the router is
currently powered by a generator during the evening and a DC-AC
inverter (with a quasi-sine wave) the rest of the time (it's on the
inverter now and reporting a very respectable 26 and 59 db so this may
not have any effect). I intend to hook the router up to a car battery
on permanent float, fused and converted down to 12v . The battery will
produce a clean signal and it will be better to have the router
connected 24/7.

Hope this boosts the hopes of people in the sticks (who probably
don't have to go to the expense of a Vigor afterall!).



broughcut@gmail.com

forgot to mention, I've been using the Vigor's long line firmware from
the get-go. I may try it without and see if it has any noticable effect
on the attenuation.

On 29 May 2005 22:41:08 -0700, (E-Mail Removed) wrote:

>forgot to mention, I've been using the Vigor's long line firmware from
>the get-go. I may try it without and see if it has any noticable effect
>on the attenuation.

Attenuation is the level of loss of the original signal from the exchange
to you. Changing the router firmware will not affect this (though it may
measure it slightly differently). Nothing will improve or degrade.

Whilst I am seriously struggling to believe you could be 14km from the
exchange and getting a 60dB attenuation if correct, you should be able to
receive 1Mb without any trouble. In fact, with SNR of 25dB you could get
2Mb, though I suspect BT would just laugh at you if you asked.

My mistake. I think the extended line firmware makes allowances for
poor attenuation. The line follows roads so I've taken a proper
measurment on the map, some of my estimates were slightly off. It's
10km by the most direct route, so I suppose it is unlikely to be
longer than 11-12km. Still pretty good for 1 or 2mb.

Is it usual for new exchange installations to be only 512K? I thought
BT may just have throttled the line due to the long distance, but
PlusNet are telling me I will have to wait for BT to upgrade the actual
exchange before I could go to 1mb, but that I could call BT and ask
them to turn up the gain on the line... I don't think gain has any
bearing on the speed at which the modem syncs, so are they suggesting
that this might improve the marginal attenuation and make an upgrade
more likely?

On 30 May 2005 14:42:43 -0700, (E-Mail Removed) wrote:

>My mistake. I think the extended line firmware makes allowances for
>poor attenuation. The line follows roads so I've taken a proper
>measurment on the map, some of my estimates were slightly off. It's
>10km by the most direct route, so I suppose it is unlikely to be
>longer than 11-12km. Still pretty good for 1 or 2mb.

Better than pretty good - bloody remarkable more like. In my experience
line distances are actually considerably longer than the crow flying
distance. I am, for example, 1.6km from the exchange but my line
attenuation indicates a line length of over 5km. But 12km does sound like
something of a record to me. If your attenuation is only 60dB then it
suggests a line length of only about half of what you estimate, though
there are plenty of variables involved in that.

>Is it usual for new exchange installations to be only 512K? I thought
>BT may just have throttled the line due to the long distance, but
>PlusNet are telling me I will have to wait for BT to upgrade the actual
>exchange before I could go to 1mb, but that I could call BT and ask
>them to turn up the gain on the line... I don't think gain has any
>bearing on the speed at which the modem syncs, so are they suggesting
>that this might improve the marginal attenuation and make an upgrade
>more likely?

Sounds like bollocks to me. There's no way BT would put ADSL equipment
into an exchange which is only capable of 512kb. Almost every exchange is
capable of 8Mb (there are a few exceptions).

Turning up the gain on the line is unlikely to make much difference, I
would have thought. Imagine listening to an old tape with lots of hiss.
Turn up the music, the hiss gets proportionately louder as well. I can't
see it making too much difference to the SNR which, ultimately, is what
will affect the speed you can get.

Could there be capacity issues at your exchange and what Plusnet are really
saying is that BT have to upgrade *capacity* before they start speeding up
any more users of the exchange? After all, virtual path congestion will be
far more obvious to people on faster connections.

PlusNet tell me that the line was activated at the "maximum your line
will support" but I've paid the upgrade fee this morning and they will
therefore put a request into BT, but tell me not to expect anything
since "it's already been activated at the maximum your line will
support" ...

I've asked PN to let BT know my SNR and attenuation results so they are
in a better position to make this judgment. I think I'm right in saying
noise margin can not be measured remotely and needs a user reading or
an engineer visit, so it's largely supposition on BT's part? I mean,
their website for this number still reports: "Our initial test
indicates that it is VERY UNLIKELY you will be able to get Broadband
from BT due to the very long length of your telephone line".

The exchange is 5 miles as the crow flies, 7 miles by road -- and the
line can only follow the road, there's no other place for it to go --
assuming the line doesn't meander around other homes on its way here.
We're a mile north of Rosedale on the Lastingham 01751 417XXX exchange.

Last I checked, when they had that activation threshold thing going,
only 130 people had even registered interest. The exchange doesn't
serve a great deal of homes and since it was only activated on 18 May
there are probably only a few of us on it at the moment. The online
availability checker's low-balling doesn't exactly encourage
subscriptions.

(E-Mail Removed) wrote:
> PlusNet tell me that the line was activated at the "maximum your line
> will support" but I've paid the upgrade fee this morning and they will
> therefore put a request into BT, but tell me not to expect anything
> since "it's already been activated at the maximum your line will
> support" ...
>
> I've asked PN to let BT know my SNR and attenuation results so they
> are in a better position to make this judgment.

I think that BT (& Plusnet) are in a better position of knowing your line
test results. Your router isn't calibrated & can be affected external
sources of noise (not on the line)....

BT (& PN) have got test facilities which will give them a more reliable set
of results & the only way to get the deffinite results is to have a engineer
call & run the APTS test from your end.

The figures given out by your router are just guidelines. I've had 5
routers here so far (had an ongoing problem which was always proved to be at
this end, reboots, lockups etc), Netgear, Linksys, Draytek, 3 Com, & last
but not least a Draytek. They all give different diagnostics, some even
change if you change the firmware in the unit. If BT are stating that the
line was activated at the max speed your line willl support the chances are
you've just wasted some money..

Having said all that, a little birdy has told me of changes in the near
future (along the lines of RADSL) so be patient, you may be lucky.

Knowing my luck I won't :-(

As fas as BT is concerned my line wouldn't support ADSL at all. They
activated it for kicks as per their new try and see policy.