BT80 RF3 Filter

I have a adsl line that comes over a long drop wire that is located at the best part of a thousand feet above sea level.
Consequently I get a large reduction of noise margin during the night hours.
It usually falls from 6dB to about 2 dB in the early hours. I have a Netgear DGN2200 which clings on to a connection for days at a time but at a sync of around 6.6Mb/s on a line of 47 dB attenuation. I also have a Belkin router which connects about 1 Mb/s higher but drops the connection every night.
In an attempt to improve things I "accidently" replaced the BT80 on the end of my drop wire with a BT80-RF3 filer. A new BT branded one. Imagine my surprise when the noise margin sank to about MINUS 0.2 dB every night from + 6dB.
Needless to say the original BT80 went back in place quick sharpish. The attenuation stayed at 47 dB by the way.
That will teach me to play about with things that don't concern me.

Odd, it should have had not detrimental effect at all. Did you, perhaps, connect it wrong ? This would be tricky, as it ain't exactly rocket science.

A sync of 6.6meg on a 47db line sounds good to me!

Definately connected it properly. Drop wire to A & B (Screw terminal block as it's a 80B).
Outgoing white/blue and blue/white to the A & B IDC terminals. Earth connections left unconnected (incidently these are in different order on the IDC compared to original).
I even flicked the PCB out of it's clips to make sure of the connections.
Left it in position for three nights and when I took it out the normal results were obtained.
I did wonder if the common mode choke had a shorted turn, it looks a bit flimsy.
Anyway back to the draining board.

With the Belkin I can get a sync of 8 Mb/s but it drops every night.
It is a EO line 'so perhaps not many joints in it.
As you say it's certainly reasonable for a line that's got to be about 3.5 km even if it comes by the most direct route.

Have you ever tried a 2wire 2700HGV on your line? They seem to be better than most at holding sync - and can even work when teh SNR drops to below 0dB.

I have thought about a 2 wire but I should have bought one at the time when boxed unused ones were available.
Nowadays on Ebay they all seem to be used models missing their power supplies for some reason.
I wouldn't like to pay out good money for a door-stop.
I have recently tried a Bipac 7700N which was a dismal failure until it blew up after about a week.
It wouldn't re-connect automatically when it lost sync and Billion UK sent me a firmware update within a couple of hours. This made it connect through thick and thin and the actual download speed dropped to below 1 Mb/s at night. After a couple more days it got mad hot and gave up the ghost. It went back to Amazon sharpish.
The exchange uses Infineon chipsets according to a Thomson router I had and the Billion and the Netgear use Broadcom chipsets. The Belkin uses a Infineon chipset which explains why it syncs at a much higher speed.
Unfortunately it keeps loosing it's security settings and I've lost cofidence in it.
Any ideas anyone on a decent modem router which uses a Infineon chipset and which doesn't cost a small fortune ?

Edited by deleted (Mon 24-Sep-12 15:57:07)