Day & Night Noise Margins Similar ?

My line length of about 3.5 km and the elevated position (900 ft ASL) of our home, mean that my broadband has always been a bit troublesome.
I'm on a EO line 'so no chance of an improvement any time soon.
I've tried various routers, some give me a sync speed of up to 8 Mb/s and a download speed of circa 7 Mb/s but drop the line every few hours. Normally my noise margin drops from 6dB to around 1 or 2 dB during darkness.
I have recently bought a Billion Bipac 7300N router and this connects at a sync speed which varies between 6655 and about 6640 only but the connection is rock steady. My ISP tell me that my connection is not being capped and because I can get a download speed of around 5.5 Mb/s all day, every day I am happy for the present.
What really puzzles me is the fact that with the Billion router the noise margin only drops a small amount at night, from circa 6.8 dB to 6.2 dB. It's been like this for some weeks now. Has the exchange DSLAM anything to do with this strange behaviour or is it down to the router ?

I think it's probably due to the Billion having a Broadcom chipset.
See the link in my signature - a Broadcom chipset (I use an old Speedtouch 585v6) transformed my line.

You might want to post your line's attenuation as that will help people see what your line is capable of - but it sounds pretty healthy to me

In reply to a post by b4dger:

I think it's probably due to the Billion having a Broadcom chipset.
See the link in my signature - a Broadcom chipset (I use an old Speedtouch 585v6) transformed my line.

You might want to post your line's attenuation as that will help people see what your line is capable of - but it sounds pretty healthy to me

According to several people on the t'internet the 7300N has a 3 part Trendchip chipset, the 7700N and 7800N have Broadcom.
I'm not going to prise it apart mind you, (well not while it's under warranty and still working). My previous Netgear 2200N had a Broadcom chipset but tried too hard and used to disconnect often.
The Billion reports my attenuation as 45 dB, other routers have reported between 44 and 48 dB at different times.

Sorry, I read that as a 7700. Lots of threads on TBB about 7700 and 7800 so caught me out

Suspect routers software is just ignoring the slightly dodgy frequencies (Called bins in DSL speak), and thus when these get bad at night due to ionosphere changes the router sees no real change in the noise margin.

Mr S. I was about to say much the same.

And to the OP: Also, just 0.6dB change is very small. Does the sync change? Does the actual achieved download speed change?

In reply to a post by MrSaffron:

Suspect routers software is just ignoring the slightly dodgy frequencies (Called bins in DSL speak), and thus when these get bad at night due to ionosphere changes the router sees no real change in the noise margin.

You make that sound *simples* !

That's all of us on long variable lines want!!! A router that can 'ignore' the problems and hang on to the connection. Whether it's the chipset or firmware or 'fairy dust' it's ALL lots of us ask

Edited by b4dger (Tue 16-Oct-12 17:32:57)

In reply to a post by MHC:

Also, just 0.6dB change is very small.

Hence the thread!?

In reply to a post by b4dger:

In reply to a post by MHC:

Also, just 0.6dB change is very small.

Hence the thread!?

And hence my follow on questions.

In reply to a post by b4dger:

That's all of us on long variable lines want!!! A router that can 'ignore' the problems and hang on to the connection. Whether it's the chipset or firmware or 'fairy dust' it's ALL lots of us ask

2wire 2700 ... Mine would hold a line down to -0.7dB - it got a little slow but would not drop for quite a while. I have a screen shot or two to prove it too.

The OP says "the connection is rock steady" - so I'm guessing it doesn't lose sync.

I have a 2Wire 2700 myself.
For me, on my line a 585v6 performs better but appreciate the 2700 is a great router.

Routers 'hanging on to a connection with low/negative SNRM values' is a slightly different thing though. For me an AR7 chipset router would often show a negative SNRM before eventually giving up. I remember reading many reports about these routers holding on in negative figures before dropping - and the writers thought they had made a good effort as they went to -3db etc.

The difference is to find routers that are able to manage to keep the margin well into positive figures. You don't want a router that just about hangs on when interference builds up - you want one that can ignore it and just carry on!

In reply to a post by b4dger:

In reply to a post by MrSaffron:

Suspect routers software is just ignoring the slightly dodgy frequencies (Called bins in DSL speak), and thus when these get bad at night due to ionosphere changes the router sees no real change in the noise margin.

You make that sound *simples* !

That's all of us on long variable lines want!!! A router that can 'ignore' the problems and hang on to the connection. Whether it's the chipset or firmware or 'fairy dust' it's ALL lots of us ask

The Billion GUI shows sync connection maintained for about 17 days now with internet connection just a few seconds less.
I can't use Routerstats or Routerstats Lite as they are not supported for this router 'so I have to log into the router to get the results.
I have found the lowest noise margin occurs in the early evening and the margin at that time is around 6.1dB, it slowly rises to 6.3 dB at 3am, (toilet break !) and returns to 6.7/6.8 the next morning.
I did notice it lost sync several times the first couple of nights before it became stable.
I guess that the internal software must be a bit special as with previous routers I've noticed drops of up to about 6 dB, a Belkin router would hold sync down to minus 1.5 dB but download speed when it dipped that low was a few hundred kb/s.

All interesting, thanks.

Re. RouterStats - I've used it successfully on routers that aren't officially supported
If you can view the stats via a web page then the RouterStats setup usually lets you 'grab' the data.