Extension for broadband only

[Old_nick]

Rather a lot depends on how good the line is to start with, and how close you are to sources of noise. If your router is syncing at the maximum speed possible, and you have SNR to spare, then running an ADSL extension won't make any difference. If your line is already suffering from poor SNR at the master, then adding an extra 10m of cable can make a big difference. In my situation, the interference was coming from an alarm system that was sending pulses along the cables, even when it was not armed. No amount of cable re-routing completely resolved the problem.

[RUNITDIRECT]

Like i said, each install is different, in our experience adding an extension usually make no difference at all if :-

Wired with the NTE5 that we sell with bell wire filter, OR
Wired with filtered faceplate(NTE2000/2005) so all extension are filtered of ADSL at source, OR
Wired with filtered faceplate(NTE2005) and ADSL extension is wired with NTE2000 extension kit.

[Old_nick]

Well, what is it in your NTE2000 extension kit that filters out noise picked up by the 10M of cable ? There's nothing in the filtered faceplate to do that - the ADSL side of the plate is not filtered ?

[RUNITDIRECT]

Well, what is it in your NTE2000 extension kit that filters out noise picked up by the 10M of cable ? There's nothing in the filtered faceplate to do that - the ADSL side of the plate is not filtered ?

Nothing, the same as the miles of cable coming from BT, the majority of noise is induced from the unbalance of the bell wire.

Twisted pair cable(for the ADSL pair) by it's very nature is designed to reject noise as well as possible-hence the twists!

I think we'll agree to disagree, we install data cabling all over the UK, 90M horizontal runs can make no difference to the ADSL performance, if you have ADSL performance drop off on only 10M of cable then it's time to look into what is causing the noise & rectify it.

If it is RF based then a BT 80A RF2 over the pair will cure it.

By the way, it isn't our NTE2000 extension kit, it's a BT Openreach branded extension kit made by Pressac UK.

[Old_nick]

The majority of noise caused in BT's underground network is crosstalk from other cables in the bundle (other ADSL pairs), and from noise radiated by other nearby cables. Noise pickup by the bell wire is only a problem in the end-user's premises.

Twisted pair cable is a cheap and cheerful way of producing a cable with noise rejecting qualities, but unfortunately the noise rejection of the twisted pair diminishes with frequency - the cables were never designed to carry anything higher than 7kHz.

As I said before, if a line is working at its full potential, with SNR to spare, then 10M of extra cable is unlikely to affect it. If a line is already working at reduced speed because of SNR problems caused by the length of BT's cable, then the noise pickup from the extra cable will affect it, because all cables (even twisted pair) pick up noise.

I know what was causing my problems - I am on a long line which is aluminium over part of the route back to the exchange, and the bottom line is that although the attenuation of the cable is only 42dB, the SNR at the test socket only allows the line to sync at about 2.5M with a 7dB margin. This margin would be quite easily eaten up by the noise radiated by an old burglar alarm system if I extended the ADSL cables, which is why the router is connected directly to the ADSL output of the filtered faceplate with as short a cable as possible.



Lastly, any RF filter which operates in the same frequency range as ADSL will filter out the ADSL at the filter frequencies too, so you won't gain anything. An ADSL router or modem acts as its own filter, because it avoids bins which are affected by interference.

[RUNITDIRECT]

Lastly, any RF filter which operates in the same frequency range as ADSL will filter out the ADSL at the filter frequencies too, so you won't gain anything. An ADSL router or modem acts as its own filter, because it avoids bins which are affected by interference.

I never said the 80A RF2 operated at ADSL frequencies. BT are claiming the RF filter as used in the I Plate can help ADSL performance, a BT 80A RF2 would offer the same results.

I am not disputing you should always try and plug into the master socket(as i have said numerous times), what i am disputing however is 10m of extension cabling will have any affect what so ever in the majority of cases.

[Old_nick]

The BT 80A RF2 is a filter for use with telephones, and is designed to filter out MW/LW interference. It is known to cause problems with ADSL, which isn't really surprising, since ADSL and MW/LW radio use the same frequencies. The correct filter for use with ADSL is the BT 80A RF3.

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[RUNITDIRECT]

yes sorry, 80A RF3 is the same filter that the i Plate features.

[dubbsy]

Thanks for all the replies,

I can give you an update on where I am on the original question.
I found that I have no BT master socket, but have an NTL one, looks the same but no BT logo, so I told BT and they are due on Friday to put me a new one in.

I have no extentions on the master, just my phone and the router, + the sky HD box plugged in with a splitter they supplied.
My main concern is that altough I am on BB base, the speed is just 0.33mb which is killing me. I am about 2 clicks from the exchange, so I am concerned about loosing speed, as I mentioned my office is about a 20 metre run from the master so I will have to run a cable or rely on the wireless.
Do I connect the 20 meter cable into the router and then to the lan socket on my PC ?

My stats are the following
Connection speed - d/stream = 384 u/stream = 412
Line Att d/steam = 59.5db u/stream = 34.0db
Noise Margin d/stream = 7.4db u/stream = 15.0db

Any ideas on how I can increase speed without spending more on upgrades

I am a Tecnical engineer but on vehicles not BT stuff so sorry if it seems vauge

[RUNITDIRECT]

In your situation it would be best to plug the router into the master socket and then run a 20M ETHERNET cable to your PC. If this is not possible then all you can do is fit an extension to where the PC is.