8900AX-2400 S/N continuosly drops over time

[ardsar]

The 8900AX has been returned so i can not provide any further info. I spent 3 months with the same issue with the D7000, ended up getting banded on the line due to forced re-syncs when the S/N dropped. As i have tried to point out, you can clearly see the behaviour or the handling of the frequency bins is different. Where the interference occurs, the bins are marked as unusable - hence the gaps appearing in the bin loading graph. Older broadcom devices such as the 8800AXL did not have this characteristic on the Bins, and bit swapping performed as normal.

Remember i am banded therefore my max speed is 22400. Broadcom can not claim to have made performance improvements because after 4 days my S/N has dropped by 3 or 4 dB yet speed still at 22400. A quick re-sync will return the S/N to 8dB at a sync of 22400

Unless anyone else has an issue, i would forget about my problem - broadcom were not interested and i have not heard back from Netgear in over 6 months.

[mognog]

i would forget about my problem - broadcom were not interested and i have not heard back from Netgear in over 6 months.

Hi ardsar,

I’m sorry you haven’t managed to solve this mystery. As someone who works in IT I hate being defeated by seemingly unsolvable problems and there is usually an answer somewhere. It’s just about narrowing down the issue until the answer is revealed. However my knowledge is very limited in this area but I do own the 8900AX-2400 so am quite happy to help try different things if you like. Just let me know.

[gatekeeper]

I very much echo mognog's sentiments on this.

[gmorgan]

I've just set my 8900 up and it's the first Billion that's disappointed me, significant drop in connection speed compared to my 8800 and my snr is dropping alarmingly, we will see if it recovers over night.

[gatekeeper]

"....... my snr is dropping alarmingly ......". This is ambiguous. Do you mean that the snr is going towards zero, or do you mean that it's becoming a higher value than the default 6dB? Say, 9 or 10dB, maybe even more? 'Going towards zero' means that the line may be able to support a higher tolerance of noise and crosstalk before unacceptably high amounts of errors occur.

The fact that you're observing that your connection speed has dropped, compared to what you had before, would surely indicate that the snr is moving to a larger and larger value, rather than moving towards zero.

I'm assuming that what you mean is that the snr is moving towards zero. Hmm, the line's operation moving away from the default target snr of 6dB towards zero - and usually that only happens if the user tweaks the line, which you can't do with VDSL - would normally mean that your modem (the modem part of the 8900) and the DSLAM have jointly agreed that your line may be able to support a higher connection speed.

You clearly need to give the 8900 some time to settle. It might just be that at the moment it's merely 'testing the waters' to see if the speed can usefully be raised (though my understanding was that, under VDSL, Openreach doesn't permit the snr to be set to a lower value than 6dB). So the snr might well return to somewhere near 6dB (or even higher) in due course.

Keep us informed, as it certainly seems as if the 8900 can behave in a strange way at times.

BTW, what's the length of your line, back to the street cabinet? Is your line normally subject to a lot of spurious noise? Did you run at VDSL with the 8800 and, if so, what sort of day-to-day working snr did the 8800's GUI report?

[gmorgan]

"....... my snr is dropping alarmingly ......". This is ambiguous. Do you mean that the snr is going towards zero, or do you mean that it's becoming a higher value than the default 6dB? Say, 9 or 10dB, maybe even more? 'Going towards zero' means that the line may be able to support a higher tolerance of noise and crosstalk before unacceptably high amounts of errors occur.

The fact that you're observing that your connection speed has dropped, compared to what you had before, would surely indicate that the snr is moving to a larger and larger value, rather than moving towards zero.

I'm assuming that what you mean is that the snr is moving towards zero. Hmm, the line's operation moving away from the default target snr of 6dB towards zero - and usually that only happens if the user tweaks the line, which you can't do with VDSL - would normally mean that your modem (the modem part of the 8900) and the DSLAM have jointly agreed that your line may be able to support a higher connection speed.

You clearly need to give the 8900 some time to settle. It might just be that at the moment it's merely 'testing the waters' to see if the speed can usefully be raised (though my understanding was that, under VDSL, Openreach doesn't permit the snr to be set to a lower value than 6dB). So the snr might well return to somewhere near 6dB (or even higher) in due course.

Keep us informed, as it certainly seems as if the 8900 can behave in a strange way at times.

BTW, what's the length of your line, back to the street cabinet? Is your line normally subject to a lot of spurious noise? Did you run at VDSL with the 8800 and, if so, what sort of day-to-day working snr did the 8800's GUI report?

We are all informed users here, my line usually can go as low as 1.6db before a reconnection and I see a .2db downward swing per evening usually. The 8900 gives me an attainable rate of 62mb, the 8800, 67mb. The 8800 connects at 56mb, the 8900, 52mb that's a drop. The 8900 also has more hec errors per hour than the 8800. The recent Sky Q hub which I believe also has a new Broadcom chipset has very similar quirks.

The line was measured just over 600m. I usually get about 20 hec errors per hour on the 8800, the 8900 had over a hundred in the same period.

The 8800 usually keeps a 6.3db sir and then goes to 6.1db in the evenings, the 8900 was down to 5.6db in 2hours.

[mognog]

Hi gmorgan,

Just out of interest are you connecting as a one box solution (using the dsl port) or using your existing openreach modem (using the Ethernet port)?

I'm using the all in-one solution and have my maximum speed of 72Mbps down & 19.9Mbps up. (using speedtest.net).
My snr (last time I checked seems to of settled on 7.6db down and 15.1db up)
I'll check again tonight to see if there has been any movement on this.

You can of course try swapping your dsl/Ethernet cable to a new one (or shorter one) just in case its faulty.

Thanks

mognog

[gmorgan]

Thanks for your reply, it's a one box solution. I've got got custom made cables, which I have made to the highest spec possible and the shortest distance where the equilibrium is perfect between distance, speed and noise.