Very close to exchange but high attenuation?

According to Sam Knows my new digs are 245 metres straight line distance from the Earls Court exchange. I have been syncing at 3900 kbps and that just didn't sit right given how close I am to the exchange. I checked the telephone wiring at the master socket and disconnected a few unnecessary wires (bell wire and second socket) and I'm now syncing at 6400 kbps, not a bad increase.

However I'm migrating to C&W LLU in a week or so and my attenuation seems rather high given my distance from the exchange and will likely hold back my ADSL2+ speeds quite substantially:

ADSL Link - Downstream - Upstream
Connection Speed - 7104 kbps - 448 kbps
Line Attenuation - 41.0 db - 24.5 db
Noise Margin - 6.6 db - 21.0 db

Does that figure seem high to people in the know and is there anything I can do to lower it? Is it likely I could get a BT engineer out for a problem such as this, if indeed it is a problem?

Edited by benjones (Wed 24-Mar-10 11:49:52)

Your D/S Attenuation indicates your line length from exchange is about 3 km, despite the 245 metres straight line distance. Your Sync speed is about right if you are on IPStream/ADSL1; on LLU/ADSL2+ you'll get about 8.5 Meg.

Yeah but why would that be the case when my exchange is literally around the corner. Surely there's no way my actual line length is 3.5 km, even if it was going some crazy route?! There are no rivers or bridges to cross, it's just a few metres down the road:

Google Map

Edited by benjones (Wed 24-Mar-10 14:16:20)

Are you 100% certain that you are connected to that exchange and not a different one?

100% sure as Vivaciti have been trying for the past month to migrate me over to the LLU equipment in that exchange.

Very strange. The sync is pretty much in line with that attenuation figure so it can't really be misreported.

You don't have a 2Km extension lead do you?

Lol! No if I did I would plug my router directly into the exchange to see if it fixed my problem!

What sort of attenuation should be expected when this close to an exchange?

Edited by benjones (Fri 26-Mar-10 12:09:25)

In reply to a post by benjones:

Lol! No if I did I would plug my router directly into the exchange to see if it fixed my problem!

What sort of attenuation should be expected when this close to an exchange?

Maybe it's just poor quality cable. Attenuation doesn't indicate distance - it indicates how much signal is lost between the exchange and you. Cable length is just the most common cause.

Having written that I know someone whose rear garden backs onto the exchange but their cable goes all the way out and along the high street before coming back. They only get about 6Mb/s :-/

In reply to a post by Andrue:

Maybe it's just poor quality cable. Attenuation doesn't indicate distance - it indicates how much signal is lost between the exchange and you. Cable length is just the most common cause.

While I'm not saying it isn't cable quality I think they'd have to be using spaghetti to make what should probably be 500m have 41dB attenuation.

Given the assurance that the line really does go to the exchange down the road I can only conclude that it must do so by the scenic route. Unfortunately getting BT to alter it is likely to be impossible

Earls Court, tube lines, big building in area, cable routes in London cannot follow straight lines, and also buildings with more than one flat can add a fair bit of cable in getting between the different properties.

So while it does not look good, without knowing the exact location of you and exchange one cannot say if it looks stupid or not