Re: adsl parameters: ideal readings?

tg wrote:
> I've got a vonaq500 adsl tester but as a beginner doing a normal (UK) adsl
> test I don't know what would constitute ideal readings.
> The readings given by the tester are:
>
> LIne Rate (kb/sec)
> Attainable rate (kb/sec)
> SNR margin (dB)
> Attenuation (dB)
> Output Power (dBm)
>
> the first two readings are obvious but for the rest of them I don't know
> how to tell what's good ot bad.
> my own broadband always works fine and the readings I got from that were:
>
> up down
> LIne Rate (kb/sec) 448 5408
> Attainable rate (kb/sec) 1120 5984
> SNR margin (dB) 24.0 9.3
> Attenuation (dB) 17.0 32.0
> Output Power (dBm) 11.9 19.8
>
> this gives me a rough idea but it would good to know what 100% ideal
> readings should look like. My ISP said the SNR upstream was a bit high but
> didn't say what it should be.
> Thanks for any advice.
>

High SNR is a good thing.

The surprising thing about your stats is the low down line rate.

For an attenuation of 32.0 I would expect much better. You might want to
check your internal wiring to see if this is bringing down the down SNR
and hence the down line rate.

The best way to do this is to plug the router into the master socket
after you have disconnected your internal telephone extension lines.

Nick wrote:
> tg wrote:
>> I've got a vonaq500 adsl tester but as a beginner doing a normal (UK)
>> adsl
>> test I don't know what would constitute ideal readings.
>> The readings given by the tester are:
>>
>> LIne Rate (kb/sec)
>> Attainable rate (kb/sec)
>> SNR margin (dB)
>> Attenuation (dB)
>> Output Power (dBm)
>>
>> the first two readings are obvious but for the rest of them I don't know
>> how to tell what's good ot bad.
>> my own broadband always works fine and the readings I got from that were:
>>
>> up down
>> LIne Rate (kb/sec) 448 5408
>> Attainable rate (kb/sec) 1120 5984
>> SNR margin (dB) 24.0 9.3
>> Attenuation (dB) 17.0 32.0
>> Output Power (dBm) 11.9 19.8
>>
>> this gives me a rough idea but it would good to know what 100% ideal
>> readings should look like. My ISP said the SNR upstream was a bit high
>> but
>> didn't say what it should be.
>> Thanks for any advice.
>>
>
> High SNR is a good thing.
>
> The surprising thing about your stats is the low down line rate.
>
> For an attenuation of 32.0 I would expect much better. You might want to
> check your internal wiring to see if this is bringing down the down SNR
> and hence the down line rate.
>
Ah, but it critically depends in the SNR. That you can measure. Actual
attenuation merely estimates the actual power fed in at the far end,
compared with what you are seeing.

This would appear to be a fairly noisy line with some rather high noise
margin applied at the DSLAM in an attempt to gain stability: On a good
line you can receive down well below 5dB SNR. Mine here is running at
similar SNR - about 9 - and similar rates, but showing a 50dB attenuation.



> The best way to do this is to plug the router into the master socket
> after you have disconnected your internal telephone extension lines.

I doubt that would show any different.,. For whatever reason the noise
is highish.

The Natural Philosopher wrote:
> Nick wrote:
>> tg wrote:
>>> I've got a vonaq500 adsl tester but as a beginner doing a normal (UK)
>>> adsl
>>> test I don't know what would constitute ideal readings.
>>> The readings given by the tester are:
>>>
>>> LIne Rate (kb/sec)
>>> Attainable rate (kb/sec)
>>> SNR margin (dB)
>>> Attenuation (dB)
>>> Output Power (dBm)
>>>
>>> the first two readings are obvious but for the rest of them I don't know
>>> how to tell what's good ot bad.
>>> my own broadband always works fine and the readings I got from that
>>> were:
>>>
>>> up down
>>> LIne Rate (kb/sec) 448 5408
>>> Attainable rate (kb/sec) 1120 5984
>>> SNR margin (dB) 24.0 9.3
>>> Attenuation (dB) 17.0 32.0
>>> Output Power (dBm) 11.9 19.8
>>>
>>> this gives me a rough idea but it would good to know what 100% ideal
>>> readings should look like. My ISP said the SNR upstream was a bit
>>> high but
>>> didn't say what it should be.
>>> Thanks for any advice.
>>>
>>
>> High SNR is a good thing.
>>
>> The surprising thing about your stats is the low down line rate.
>>
>> For an attenuation of 32.0 I would expect much better. You might want
>> to check your internal wiring to see if this is bringing down the down
>> SNR and hence the down line rate.
>>
> Ah, but it critically depends in the SNR. That you can measure. Actual
> attenuation merely estimates the actual power fed in at the far end,
> compared with what you are seeing.
>
> This would appear to be a fairly noisy line with some rather high noise
> margin applied at the DSLAM in an attempt to gain stability: On a good
> line you can receive down well below 5dB SNR. Mine here is running at
> similar SNR - about 9 - and similar rates, but showing a 50dB attenuation.
>

Ok I won't pretend to know what I'm talking about, but...

AIUI The DSLAM sets a high target SNR due to variations in SNR and
consequent LOS. Line Rate will come down with SNR I think ball park
figures are something like 1000 kb/sec increase in line rate for 6db
decrease in SNR.

Line rate tends to be correlated with attenuation. If you are a fair way
below the average it is worth checking internal wiring for something
that maybe adding noise to the line.

>
>
>> The best way to do this is to plug the router into the master socket
>> after you have disconnected your internal telephone extension lines.
>
> I doubt that would show any different.,. For whatever reason the noise
> is highish.

From a position of considerable ignorance I would say I do suspect
internal wiring may make a difference.

Hopefully the OP will post the results of my suggested investigation
and I can then either stick my tongue out at you or slink away quietly
and change my posting id ;o)