Best modem for low SNR

Hi All,

Being some distance from my local exchange (>6km) I've got quite a high line
attenuation, so according to the line tests cannot go above 1M download.

My question: Does the modem's SNR capability have significant effect in all
this? Are all modems the same, or are some makes better than others at
decoding low SNR signals? I could really do a recommendation for the best
modem in this respect (preferably ethernet or an ethernet modem/router), or
possibly a link to a comparison chart that includes low signal performance.

Thanks!

Mark.

"markp" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Hi All,
>
> Being some distance from my local exchange (>6km) I've got quite a high
> line attenuation, so according to the line tests cannot go above 1M
> download.
>
> My question: Does the modem's SNR capability have significant effect in
> all this? Are all modems the same, or are some makes better than others at
> decoding low SNR signals? I could really do a recommendation for the best
> modem in this respect (preferably ethernet or an ethernet modem/router),
> or possibly a link to a comparison chart that includes low signal
> performance.
>
> Thanks!
>
> Mark.
>
Hi Mark, just out of interest what are your attenuation values for your
current set up. Mine run
DS Line Attenuation 15
US Line Attenuation 6

Gio

>
>

>>
> Hi Mark, just out of interest what are your attenuation values for your
> current set up. Mine run
> DS Line Attenuation 15
> US Line Attenuation 6
>
> Gio

Hi Gio,

Currently DS line attenuation 62bB, US line attenuation 31.5dB, DS SNR
margin 10.8dB, US SNR margin 26dB. That's what my modem/router tells me!

Mark.

markp wrote:
>> Hi Mark, just out of interest what are your attenuation values for your
>> current set up. Mine run
>> DS Line Attenuation 15
>> US Line Attenuation 6
>>
>> Gio
>
> Hi Gio,
>
> Currently DS line attenuation 62bB, US line attenuation 31.5dB, DS SNR
> margin 10.8dB, US SNR margin 26dB. That's what my modem/router tells me!
>
> Mark.

I have similar figures and reliably get 1mb.

Gaz

markp wrote:
> Hi All,
>
> Being some distance from my local exchange (>6km) I've got quite a high line
> attenuation, so according to the line tests cannot go above 1M download.
>
> My question: Does the modem's SNR capability have significant effect in all
> this? Are all modems the same, or are some makes better than others at
> decoding low SNR signals? I could really do a recommendation for the best
> modem in this respect (preferably ethernet or an ethernet modem/router), or
> possibly a link to a comparison chart that includes low signal performance.
>
> Thanks!
>
> Mark.
>

Apparently, routers using a "TI" chipset (rg. ZyXEL), as opposed to a
Conexant (eg. Mercury et al), do better on long/poor quality lines.

Living within spitting distance of my exchange, I've got no way of
verifying that personally, however.

xF,

....Nick

"Nicholas Thomas" <ku.gro.snagap-(E-Mail Removed)> wrote in
message news:446a53ba$0$640$(E-Mail Removed)...
>
> Apparently, routers using a "TI" chipset (rg. ZyXEL), as opposed to a
> Conexant (eg. Mercury et al), do better on long/poor quality lines.
>
> Living within spitting distance of my exchange, I've got no way of
> verifying that personally, however.
>
> xF,
>
> ...Nick

Very interesting you should say that, I've just had a reply in an ISP forum
to the same question by a guy who installs ADSL routers for a living. He
recommended ZyXEL as they seem to hold on to low strength signals better
than the others. Also Netgear DG834G is supposed to be pretty good, again I
think based on a TI chipset.

Thanks!

Mark.

"markp" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Hi All,
>
> Being some distance from my local exchange (>6km) I've got quite a high
> line attenuation, so according to the line tests cannot go above 1M
> download.
>
> My question: Does the modem's SNR capability have significant effect in
> all this? Are all modems the same, or are some makes better than others at
> decoding low SNR signals? I could really do a recommendation for the best
> modem in this respect (preferably ethernet or an ethernet modem/router),
> or possibly a link to a comparison chart that includes low signal
> performance.


Not really an expert on such matters but I would say it doesn't matter as
the
SNR is a property of the signal rather than the modem. Maybe modems
have different thresholds for what is signal or what is noise, but it cannot
'know' what is noise and what is signal. If it has a low margin of
difference
it might detect more 'signal' but a lot of that would really be noise so it
would give an error and require a 'resend' or something.
Another aspect might be the internal noise generated by the modem
but I imagine that would be pretty negligible compared to the line noise.
I suppose what you would really want is a modem where you could vary the
signal and noise levels to suit your line conditions.
Infact I might knock one up myself as I am feling a bit bored.
Another alternative is to move closer to the exchange :O)
So basically I have no idea other than to say that if you have
a 'crap' signal, the best you are going to get is a 'crap' signal,
no modem can change that! Having said that some radios work
better with a crap signal than others but thats more due to a better
aerial I would imagine.
Generally speaking more expensive models should have higher
tolerance components but I don't know if that would be signifcant.
A high quality cable to connect from the socket to the modem
might help though, especially if you live in a noisey electrical
enviroment, but as its probably a fraction of 1% of the total cable
lenght it is clutching at straws a little. However it certaintly can make
a considerable difference in the quality of a TV signal from its
aerial. A good quality flylead improved my digital TV signal
significantly, but you can't make a silk purse out of a cows
ear and I would assume the cable you already have is of good
quality? Your cable is probably quite close to a lot of electrical
equipment, as would be your modem, so it might help if the modem
was not sitting on top of your computer etc... I don't really know if
it would help but it cant do any harm.



>
> Thanks!
>
> Mark.
>
>
>

In article markp says...
>
> "Nicholas Thomas" <ku.gro.snagap-(E-Mail Removed)> wrote in
> message news:446a53ba$0$640$(E-Mail Removed)...
> >
> > Apparently, routers using a "TI" chipset (rg. ZyXEL), as opposed to a
> > Conexant (eg. Mercury et al), do better on long/poor quality lines.

> Very interesting you should say that, I've just had a reply in an ISP forum
> to the same question by a guy who installs ADSL routers for a living. He
> recommended ZyXEL as they seem to hold on to low strength signals better
> than the others. Also Netgear DG834G is supposed to be pretty good, again I
> think based on a TI chipset.


Guess I need to contact http://www.billion.uk.com/tomorrow to see if
they use 'TI' in their upcoming modems/router release - no solid
prices yet. Their CEO, Tim Chen spent a happy 30mins at Infosec
going through the bells and whistles with me that I've not seen on
other consumer/soho products, such as built in SSL tunneling, twin WAN,
packet filtering and some very nice VoIP ADSL2+
Just waiting a while to see some reviews while my old Draytek slowly
melts away!


badger

Draytek Vigor 2600 range has special firmware for 'UK long lines', probably
also for other models.
Works for me, I have Att of 50 and SNR average of 8 on 5km line.
ADSL max synchs from 2,112,000 to 2,644,000, but actual download speed, as
measured by PlusNet,
is 1,432,000.
You can find Drayteks on Ebay at reasonable prices and they are rock solid,
so no worries there.
That's how I got mine.
Regards,
Martin

In article Martin² says...
> Draytek Vigor 2600 range has special firmware for 'UK long lines', probably
> also for other models.
> Works for me, I have Att of 50 and SNR average of 8 on 5km line.


Thank's for this!

Somehow the firmware info past me by during my irregular visits
to the forums.


badger