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.