FTTC Output Power Levels v Sync Speed

[Bald_Eagle1]

Hi All,


I have recently noticed from my HG612 modem's GUI that my DS Output Power levels fluctuate a little, quite often between GUI screen refreshes, so I have graphed power levels to get a visual idea of what it looks like.


The first graph is from a 18Mb Sync speed FTTC connection.
The second graph is from my 30Mb Sync speed FTTC connection
The third graph is from a 40Mb Sync speed connection








Just concentrating on DS Output Power levels for now, the difference in pure visual appearance is clear.

My own connection has been rather unstable over the last 7 months or so, eventually having a DLM reset 10th March, which initially provided a 35Mb sync speed for the first time since July 2011.

I first thought that stability had also improved, but following a number of "on the fly" resyncs at lower speeds, it is back down to 30Mb Sync speed, with Attainable rates around 33Mb to 36Mb, depending upon the time of day.

The 18Mb connection is stable, but around 1600m from the cabinet.
The 40Mb connection is also stable & around 500m from the cabinet.
My own 30Mb connection does not appear quite so stable & the 4 day graph above shows fluctuations in DS Output Power levels, whereas the other 2 connections show very steady Output Power levels.

I also notice the differences in DS Output Power levels for all 3 connections is not massive, despite the large differences in sync speeds.
The whole range is only between 11 dBmV & 13.7 dBmV.

I have seen other Output Power graphs from other users with varying speed connections & they also look steady.


The Windows Ongoing data harvesting script already stores any changes to Output Power levels, but the released graphing scripts do not plot the graphs (yet).



If anyone on the 80/20 trial would like to send me a copy of their ongoing modem_stats.log, could you please contact me via PM for an email address, or if you already have my email address, could you please forward a copy to me?
Alternatively, could you please upload the log file somewhere & post a link to where I could download it?
I will provide the graphs by return email, or post them here.


Does anyone know if the Output Power levels come from the actual sync speeds, or are sync speeds dictated by Otput Power levels?


Does anyone know if fluctuating power levels are a symtom or a cause of an unstable connection, or is it a "normal" phenomenon?

Paul.

[Steve]

From adsl, although I don't know specific power level settings but my understanding is that the level is set at the minimum level required to maintain a given margin without causing undue interference i.e. crosstalk.

[Bald_Eagle1]

From adsl, although I don't know specific power level settings but my understanding is that the level is set at the minimum level required to maintain a given margin without causing undue interference i.e. crosstalk.

Thanks Steve,

That sounds like a reasonable explanation.

I would still like to compare stats from other users, but from the few that I have seen so far, it looks like only mine fluctuates so much.
Could this possibly explain some of the "issues" I have experienced to date?

I am currently using a version 2B HG612 modem.
The next time I feel a reboot coming on, I'll try out another HG612 modem to see if the same effect is still present.

[Steve]

Do I need to update your software to get the Output levels as I can't see it in the stats I posted in the other thread?

[Bald_Eagle1]

Hi Steve,

Do I need to update your software to get the Output levels as I can't see it in the stats I posted in the other thread?

I haven't released the updated scripts yet as I am still playing about with them.

If you wanted to forward the whole modem_stats.log to me I could generate the graphs for different periods for you & send them back to you.

Paul.

[Steve]

I can send you a short log with gaps.