Broadband drops constantly with router, works fine with USB modem

Hello. I've been trying to get a home wireless network set up for ages
and I've tried a DLink and recently the netgear RangeMax ADSL modem /
router. But for both, I suffered from the ADSL link dropping every
couple of minutes. I emailed Netgear and asked them what was
happening, and they said it was a problem with noise attenuation - I
had 50db of noise (I'm about 5km from the exchange) and the Netgear
DG834PN can only cope with a maximum of 20db before it cuts off. I'm
guessing that was the problem with the DLINK WAG54 too that I had
before. The thing is, when I connect with a USB modem (SAGEM F@ST 800)
it works almost every time and stays connected for days, weeks even.

So my question is - why is it that integrated wireless routers / ADSL
modems can't cope with noise on the line whereas a bog standard £5 USB
modem can? Has anyone come across a good integrated wifi router modem
that can handle a bit of line noise yet? Or is there a way to connect
my reliable SAGEM USB modem via a wireless router?

Any suggestions gratefully received.

(E-Mail Removed) wrote:
> Hello. I've been trying to get a home wireless network set up for ages
> and I've tried a DLink and recently the netgear RangeMax ADSL modem /
> router. But for both, I suffered from the ADSL link dropping every
> couple of minutes. I emailed Netgear and asked them what was
> happening, and they said it was a problem with noise attenuation - I
> had 50db of noise (I'm about 5km from the exchange) and the Netgear
> DG834PN can only cope with a maximum of 20db before it cuts off. I'm
> guessing that was the problem with the DLINK WAG54 too that I had
> before. The thing is, when I connect with a USB modem (SAGEM F@ST 800)
> it works almost every time and stays connected for days, weeks even.
>
> So my question is - why is it that integrated wireless routers / ADSL
> modems can't cope with noise on the line whereas a bog standard £5 USB
> modem can? Has anyone come across a good integrated wifi router modem
> that can handle a bit of line noise yet? Or is there a way to connect
> my reliable SAGEM USB modem via a wireless router?
>
> Any suggestions gratefully received.

The DG834G netgear which i am currently using says:

ADSL Link Downstream Upstream
Connection Speed 1152 kbps 288 kbps
Line Attenuation 59 db 15.5 db
Noise Margin 11 db 19 db


with no problems.

I have also used 3com office connect on the line with no problems. Some
routers are much better on long lines, do a quick check on this newsgroup
for a list of long line routers.

Gaz

(E-Mail Removed) wrote:
> Hello. I've been trying to get a home wireless network set up for
> ages and I've tried a DLink and recently the netgear RangeMax ADSL
> modem / router. But for both, I suffered from the ADSL link
> dropping
> every couple of minutes. I emailed Netgear and asked them what was
> happening, and they said it was a problem with noise attenuation - I
> had 50db of noise (I'm about 5km from the exchange) and the Netgear
> DG834PN can only cope with a maximum of 20db before it cuts off.
> I'm
> guessing that was the problem with the DLINK WAG54 too that I had
> before. The thing is, when I connect with a USB modem (SAGEM F@ST
> 800) it works almost every time and stays connected for days, weeks
> even.
>
> So my question is - why is it that integrated wireless routers /
> ADSL
> modems can't cope with noise on the line whereas a bog standard £5
> USB
> modem can? Has anyone come across a good integrated wifi router
> modem that can handle a bit of line noise yet? Or is there a way to
> connect my reliable SAGEM USB modem via a wireless router?
>
> Any suggestions gratefully received.

Your SNR reading is very suspect & I very much doubt if you really do
have a SNR of 50dB, Loop attenuation/loss maybe but not SNR, try
rebooting your router & reporting back the line status stats after it
first resynchs.

By the way a SNR of 50dB is very good whilst a Loop loss 50dB isn't to
bad either...

(E-Mail Removed) wrote:
> Hello. I've been trying to get a home wireless network set up for ages
> and I've tried a DLink and recently the netgear RangeMax ADSL modem /
> router. But for both, I suffered from the ADSL link dropping every
> couple of minutes. I emailed Netgear and asked them what was
> happening, and they said it was a problem with noise attenuation - I
> had 50db of noise (I'm about 5km from the exchange) and the Netgear
> DG834PN can only cope with a maximum of 20db before it cuts off. I'm
> guessing that was the problem with the DLINK WAG54 too that I had
> before. The thing is, when I connect with a USB modem (SAGEM F@ST 800)
> it works almost every time and stays connected for days, weeks even.
>
> So my question is - why is it that integrated wireless routers / ADSL
> modems can't cope with noise on the line whereas a bog standard £5 USB
> modem can? Has anyone come across a good integrated wifi router modem
> that can handle a bit of line noise yet? Or is there a way to connect
> my reliable SAGEM USB modem via a wireless router?
>
> Any suggestions gratefully received.
>

The important figure isn't really attenuation (although that defines a
theoretical maximum sync speed) - rather, it's the SNR (signal to noise
ratio) margin that you need to be most worried about. It's a measure of
how strong the ADSL signal is, compared to background noise.

My experience has always been that adsl routers have performed better
than USB modems for synchronising - but that experience is fairly
limited . What immediately comes to mind, though, is that when your
telephone cable is plugged into the router, it's running past a source
of interference... say, monitor, power brick, central heating, etc...
whereas, plugged into the USB modem, it isn't. You might want to get
some data on relative sync speeds and SNR margins achieved with both
router and modem, and try stacking them on top of each other - see if
location makes any difference.

Another alternative is that your particular router is just
over-optimistic when it comes to working out the maximum speed it can
support (this is assuming you're on MAX?), so sets up for a particular
speed - which it can't support - then drops.

Assuming that the routers are synching faster than the modem, you just
need to increase your target SNR (hit your ISP with a cluebat for this),
until the router syncs at a comparable speed to the modem.

Or, do as I did with this problem and get an ISP out. It could well be
general low line quality (for me, several joints got remade; I was
syncing at 8128, but dropping the connection every minute or so - the
wires were corroded, and regularly injecting extreme noise peaks into
the connection, forcing it to drop). Again, ISP + cluebat is necessary.

As for your other query, the only thing that comes to me off-hand is
getting your PC to act as a wireless host, and setting up IP forwarding
between the wireless and ADSL. I've got absolutely no idea how you'd do
that in Windows, unfortunately... I defected to linux (under which, such
operations are trivial) shortly after XP came out, so never bothered to
familiarise myself with it. Maybe someone who's bothered to read the
newest version of the Necronomicon (updated with key texts from the
Lesser Key of Solomon, AIUI) can inform you as to the correct arcane
chants and sacrifices to get such a thing working...

xF,

....Nick

In a fit of madness, Nicholas Thomas wrote:

> Or, do as I did with this problem and get an ISP out. [...]

Erm. I meant 'engineer' there. Obviously

/me takes the cluebat to himself...

xF,

....Nick

Appreciate all the help - I didn't realise it was possible to telnet in
and adjust the SNR, so I'll have a go with that now. A bizarre thing
is happening to me - having changed nothing on my router and wireless
laptop, now when I try to connect to the web, I get a connection error
in IE, but at the same time skype still works. have disabled firewall,
etc, but still doesn't change anything. i think i'm going crazy - how
can skype work but IE not - the ADSL link is showing on router, etc.

reset the router (gawd knows why it was blocking all web connections
from coming in) - and everything seems hunky dory now, router working,
not dropping as yet...

I Just wanted to let you know that the suggestion regarding modifying
the SNR via telnet seems to have worked a treat (so far!) - I have
lowered my connection speed which is fine with me - 3000k or so d/l,
but it doesn't seem to be cutting out. Really appreciated, thanks.
Its funny, I exchanged loads of emails to Netgear technical support
(with far more info than I provided you guys in my original post) and
all they could come back with was there was too much noise on the line
for this product, and to take it back for a refund.... why didn't he
tell me to modify the SNR settings via telnet like you guys did?

thanks again for such perceptive and quick help.

(E-Mail Removed) wrote:
> reset the router (gawd knows why it was blocking all web connections
> from coming in) - and everything seems hunky dory now, router working,
> not dropping as yet...
>
> I Just wanted to let you know that the suggestion regarding modifying
> the SNR via telnet seems to have worked a treat (so far!) - I have
> lowered my connection speed which is fine with me - 3000k or so d/l,
> but it doesn't seem to be cutting out. Really appreciated, thanks.
> Its funny, I exchanged loads of emails to Netgear technical support
> (with far more info than I provided you guys in my original post) and
> all they could come back with was there was too much noise on the line
> for this product, and to take it back for a refund.... why didn't he
> tell me to modify the SNR settings via telnet like you guys did?
>
> thanks again for such perceptive and quick help.
>

Glad things are sorted. Had it been a dial-up modem, I would have
suggested "control panel->internet options->connections" and make sure
"never dial a connection" is selected as the symptoms described fit that
adjustment exactly. It's a long time since I un-installed my USB modem
software, so I don't remember how that connected!