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Attenuation too high for 2Mbit broadband, need to reduce it!


Attenuation too high for 2Mbit broadband, need to reduce it!


Ok, I was running at 2mb a few days ago, and everything seemed fine as far as I could tell. I had raised a ticket when I was first upgraded as my connection was down, for over 12 hours after the upgrade, but then it seemed to solve itself. By then, the problem was already passed onto BT anyway, and I was downgraded to 1Mbit. I've now been told my line can't handle 2Mbit.

Here's some info on a line test they did earlier, when my ADSL was down:
Downstream xDSL Link Info
Loop Loss 44 dB

I read about, noticing articles say less than 45dB or 44dB is good enough for BT to provide 2Mbit. Is there anyway I can reduce this anymore to guarantee I stay this way?. Using a D-Link 100-DSL internal modem.

Edit: There is one phone with a microfilter plugged into the master socket. The modem is plugged into a different socket (and I can't put my computer beside the master socket, and don't want to go wireless).

Posts: 2,886
Registered: 30-07-2007

Attenuation too high for 2Mbit broadband, need to reduce it!

There's nothing significant you can do, I'm afraid, apart from move house or get BT to run a new wire from your house to their exchange.
You might just check that the wiring from the master to the broadband socket is not frayed/worn, and that the connections are clean, but that's it. Perhaps run a new wire to see if it's better, but it probably won't be.

I'm surprised you've not got a reliable 2Mb connection with that figure - but your Signal to Noise Ratio is also important, and I'd guess that must be down near 10 or so. There are a number of people who run quite happily at 46 or 47, quite a bit above the 43 recommended limit, but usually with a SNR of 20-ish plus.

I tried putting new high quality filters in to improve mine, and while they made the phones better, they did nothing for the attenuation (loop loss) or SNR.
Community Veteran
Posts: 14,469
Registered: 30-07-2007

Attenuation too high for 2Mbit broadband, need to reduce it!

Line attenuation is primarily to do with the length of telephone line between you and the exchange and the quality of that line. Wiring within the house may have a small affect but this is unlikely. As stated above, there is nothing you can do to improve your line attenuation.

Also FYI the upper limit for 2Mbs speeds is 43dB and BT are becoming very strict in not allowing 2Mbs speeds on lines that are higher than this - even 1dB makes a big different to the signal strength.

Attenuation too high for 2Mbit broadband, need to reduce it!

I have a similar problem. If I plug my modem downstairs I get a line attentuation fo 15 dB.

If I plug my modem in an extension upstairs near my computer my line attentuation jumps to 47dB. I realise the length of the telephone line makes a difference but I cant seem to understand how 15 ft of extra cabling can make such a big difference? Especially, if I'm getting 15dB to my master socket....should I check the capacitance of the line?

Having scouted around for information I've been advised that I could potentially replace the wiring to my telephone socket upstairs with twisted pair cabling which is both shielded and has low loss...question it worth me trying this?

Can anyone confirm this? Also, can I not buy some sort of attenuator which will improve my line attenuation? I refuse to believe that this cannot be improved....


Attenuation too high for 2Mbit broadband, need to reduce it!

To be honest, I would have thought that if you get the best signal/quality plugged into your main BT socket, then the ideal way to get a good broadband connection would be to use a router plugged into the main/master socket with a very short lead.

If you get a wireless router you won't have to worry about using a network cable from the router to wherever your pc is - although the network speed will be effected by distance/walls etc. Still, its very unlikely to drop below the speed of you broadband connection anyhow (unless you have really bad reception/interference or a very fast BB link.. ;o).

Alternatively use a wired network lead from the router to your pc for best performance. You can either have a long cable (which can be up to 100m for ethernet network cable ;o) ) or go the whole hog and get some wall mounted rj45 sockets wired in. Also allows for future provision if you fancy some network action, or hook up you game console, on demand tv box etc etc etc..

I tend to take/recommend this approach as it removes any variables that may be introduced with phone extension leads and the like.
Community Veteran
Posts: 6,983
Thanks: 8
Registered: 10-04-2007

Attenuation too high for 2Mbit broadband, need to reduce it!


It sounds as though you are "double filtering" to the extension socket.
Have a look at the tutorial here and it will show you how to get the filtering wrong and how to correct it if it is.