Why is Attenuation and SNR different upstream and downstream?

Hi


My rural longish line shows this:

Dn Up
Signal/Noise ratio dB 12 19
Line attenuation dB 64 32


As a result my Max ADSL connection keeps dropping - currently syncs @ 1800 but can drop as low as 1400.

I have tried plugging into the master socket directly but that doesn't seem to affect it so I guess
the house wiring is OK.


Questions:

1. Given that the signal up and down is carried on the same copper, why is the attenuation different?

2. It seems that the downstream actuation is pretty high - is there anything I can do to reduce it?



TIA - Adam

"Adam Lipscombe" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Hi
>
>
> My rural longish line shows this:
>
> Dn Up
> Signal/Noise ratio dB 12 19
> Line attenuation dB 64 32
>
>
> As a result my Max ADSL connection keeps dropping - currently syncs @ 1800
> but can drop as low as 1400.
>
> I have tried plugging into the master socket directly but that doesn't
> seem to affect it so I guess the house wiring is OK.
>
>
> Questions:
>
> 1. Given that the signal up and down is carried on the same copper, why is
> the attenuation different?
>
> 2. It seems that the downstream actuation is pretty high - is there
> anything I can do to reduce it?

Move nearer to the exchange ....?

--
Graham J

Well its a heavy old house and I couldn't carry it alone....


Seriously, though...

Our cable takes a circuitous route to the exchange, but there is another BT "route" nearby that
terminates about 400 yds along the road.
As far as I can see that one has a much shorter distance to the exchange.


Is it conceivable that I could persuade BT to connect me to the other route instead? (It would need
extra poles to extend the route etc)
How would one go about it?


TIA -Adam


Graham wrote:
> "Adam Lipscombe" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
>> Hi
>>
>>
>> My rural longish line shows this:
>>
>> Dn Up
>> Signal/Noise ratio dB 12 19
>> Line attenuation dB 64 32
>>
>>
>> As a result my Max ADSL connection keeps dropping - currently syncs @ 1800
>> but can drop as low as 1400.
>>
>> I have tried plugging into the master socket directly but that doesn't
>> seem to affect it so I guess the house wiring is OK.
>>
>>
>> Questions:
>>
>> 1. Given that the signal up and down is carried on the same copper, why is
>> the attenuation different?
>>
>> 2. It seems that the downstream actuation is pretty high - is there
>> anything I can do to reduce it?
>
> Move nearer to the exchange ....?
>
> --
> Graham J
>
>

On Thu, 19 Jul 2007 12:01:29 +0100, Adam Lipscombe
<(E-Mail Removed)> wrote:

>Questions:
>
>1. Given that the signal up and down is carried on the same copper, why is the attenuation different?

Upstream operates at a lower frequency than downstream. In general the
higher the frequency, the higher the attenuation.

>2. It seems that the downstream actuation is pretty high - is there anything I can do to reduce it?

Assuming you connected into the test socket (behind the master
faceplate) and you had disconnected any extensions then no there's not
a lot you can do other than move house.

Adam Lipscombe <(E-Mail Removed)> wrote:

>1. Given that the signal up and down is carried on the same copper, why is the attenuation different?

Because the upstream uses lower frequencies and much of the attenuation is
due to line capacitance which has increasing effect with increasing
frequency.
--

Adam Lipscombe wrote:

> 1. Given that the signal up and down is carried on the same copper, why is the attenuation different?

The downstream connection operates at higher frequencies and attenuation increases with frequency.


> 2. It seems that the downstream actuation is pretty high - is there anything I can do to reduce it?

No.

Graham

"Adam Lipscombe" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Is it conceivable that I could persuade BT to connect me to the other
> route instead? (It would need extra poles to extend the route etc)
> How would one go about it?
>
>
> TIA -Adam

Well, if you had bottomless pockets, you could have a try...
BT have this thing called "excess construction charges" on top of their
standard connection charges.
People who suffer from these are typically farmers and residents of small
cottages at the end of long private driveways/tracks, where there hasn't
been phone service before.
They can end up paying thousands to get connected if a long
pole-route/underground cable has to be installed.
In this aspect, BT are no different from the other utilities - electricity
and gas, who also charge on a "cost-of-works-plus-profit" basis, the only
difference being that in rural areas, there's no mains gas anyway, so don't
even bother asking. At least BT and the electricity companies have a duty to
provide service anywhere.

George

>Well its a heavy old house and I couldn't carry it alone....

If the mountain won't come to Mohamed..., the only other way is to move the
BT exchange to you backyard !