New Netgear DNG2200

I have had a Zyxel Prestige 660HW-T1 router for a few years, and I have just bouught a Netgear DNG2200.

The router stats on the old Zyxel were

Noise margin 20 db up 6 db down
Attenuation 31 db up 53 db down
speed 448 3904

with the new DNG2200 the stats are

ADSL Link Downstream Upstream
Connection Speed 3168 kbps 448 kbps
Line Attenuation 61.0 db 29.0 db
Noise Margin 12.3 db 19.0 db

It looks like the noise margin on the DNG2200 is double that of the noise margin on the zyxel and hence why the connection speed is less.

I have tried rebooting, unplugging, the routers a couple of times but I still get the same stats.

Why should the new DNG2200 connect with a different noise margin than the Zyxel.

I was hoping that the new router would have given me a better connection speed than the zyxel.

Stephen

The noise margin is not double. How do you work that out?

The downstream noise margin for the Zyxel is 6, but for the Netgear its 12.

It's a logarithmic scale. More like 5 times.

If you want to be pedantic about it, since its logarithmic, assuming base 10, 12 is 1 million times bigger than 6, or if you are working in natural logs its 400 odd time bigger. But since most people look at the absolute figures quoted by the router, then I say it is double.

If you drop the zyxel back in now its still showing the 6dB? Have a dgn2200 and not seeing anything resembling this behaviour.

Suggestion is ISP has raised your target noise margin to 12dB now.

I have tried swapping the modem cable a couple of times between the routers and it still gives me 6db on the Zyxel and 12 on the DNG2200.

I'm trying to remember from the back of my mind if I might have tweaked the noise margin target on the Zyxel sometime in the past, but I don't think so.

What I can remember is that when I got the Zyxel it was to replace a Belkin router, and the noise margin dropped immediately when I started using the Zyxel because I had been having problems with the Belkin that had caused the noise margin target to be raised at the exchange ( my connection speed went from about 2.5meg to 3.5meg the instant I started using the zyxel). It did look at the time like the Zyxel was targeting a lower noise margin than that set at the exchange, becasue the Belkin had been about 12 and the Zyxel was 6. Would that be possible?

Is it possible to tweak the noise margin target on the DNG2200, or can I check somewhere what my target noise margin is and can I get that changed with my ISP (ADSL24)

In reply to a post by BatBoy:

It's a logarithmic scale. More like 5 times.

That would be kind of true (ish) if you were expressing noise margin as the signal strength difference between signal and noise (as a measurement of power).
Even then, and using that logic, it would be four times greater (approximately double the signal/power for every 3dB).
But expressed as a dB figure (which it is), it's just double.

Well that would be the case if you were hearing the noise, it would sound twice as loud - that's the idea behind a logarithmic scale. Unfortunately in this case, it's affecting a device which is hearing five times the noise. Unlucky

I'd stick with the Zyxel...

In reply to a post by soapysoutar:

I'm trying to remember from the back of my mind if I might have tweaked the noise margin target on the Zyxel sometime in the past, but I don't think so.

Didn't think you could do any tweaking on Zyxels unless you know some cli stuff that I don't I've used a couple of them in the past and found them to be very good, despite the fact the majority use an AR7.