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[echo92]

Hi all,

I was wondering if you could help me answer a query please With a Huawei HG533, our upstream line attenuation is reported as 31.5 dB and our downstream is reported as 56 dB - we're about 2 miles from the exchange and plotting the line route plops us in the 3.5 km line length, so the line attenuation is about right. Also, as I understand it, a rough rule of thumb is that upstream attenuation is about half of downstream, so the figures look okay.

We switched to using a Netgear DG834G v3, since, despite being 7 years old, it just guffaws at attempts to knock it off the line (whereas the HG533 would run a mile in the other direction), and the downstream line attenuation, using the same ADSL mode, is reporting as 50 dB, which is likely due to the different way the Netgear reports attenuation. The upstream attenuation is now at 15 dB however, quite a difference from the 31.5 dB reported by the HG533!

Could it be the upstream attenuation is much lower just due to the way the Netgear router is calculating the upstream frequencies compared to the HG 533? Our line is operating stably at 6 dB SNR, no noise and no disruptions, and we get around 6 Mbps which is good for our line!

[burakkucat]

Looking at the figures and doubting that there was any significant change made to the physical infrastructure of your circuit (co-coincidently at the time that you swapped from one modem/router to the other), I conclude that it is just the way that the different devices determine and report the values.

I do not attach any significance to absolute values but far prefer to consider relative values. Obviously when swapping from one device to the other there can be a significant change in the parameters reported . . . hence creating a visible "step" in the relative statistics.

I gather that you are satisfied with the overall performance of your circuit. From the information that you have provided, I will also concur.   

[kitz]

I strongly suspect that the Netgears measures the upstream attenuation based on measurement at a specific tone/frequency.   

When I was on standard adsl, Netgear 834x would report my upstream as 4dB, whilst every other router would report 7dB.

[konrado5]

I strongly suspect that the Netgears measures the upstream attenuation based on measurement at a specific tone/frequency.

Is it not depended rather on chipset than router vendor? For example, on my line D-Link DSL-2740B reports the same attenuation as TP-Link TD-W8950ND. Both have Broadcom modem.

[echo92]

Hi all,

Many thanks for the replies - that's very useful information

@burakkucat That's a useful tip to monitor relative values, thanks I was just surprised at the huge difference in reporting of upstream attenuation, though Kitz's suggestion would answer this - I guess other routers monitor a range of upstream frequencies? From what you've mentioned, I would also concur that the discrepancy is due to simply changing the routers around. As for being happy, that I am (as the family get to do what they need online). Though I may appreciate any suggestions on how I may persuade the powers that be that FTTC might be a good upgrade...

@Kitz - thanks Kitz, the reporting at a particular frequency wasn't something I knew, learn something new. Also good to know that Netgears seem to do it in general, and ours isn't trying to confuzzle me!

@konrado5 It could be due to chipset - our Netgear is running one of the Texas Instrument AR7 chipsets (I believe the v4 revision moved to a Broadcom chipset), whereas the HG533 is a Ralink (now Mediatek) chipset, though without acquiring an array of routers from a certain famous auction site it'd be hard to say. Not to mention my parents would be confused as to why we need so many routers...!