Interesting article on imminent UK bb developments

dub45

http://www.guardian.co.uk/technology/2008/apr/17/telecoms.broadbandspeeds

watty

The connection speed issue is a tricky one. The "up to 8Mbps" figure is already one of the most derided in UK broadband; according to Nielsen Online, only 3% of us live close enough to an exchange to get it. That's because broadband speeds fall off with distance from the exchange.

BT chart To understand why takes a little physics. A phone line can transmit voice and data simultaneously by sending them at different frequencies. With ADSL2, the data signal is sent on a carrier at about 1.1MHz, far above the audible range. At your telephone socket, the "splitter" then retrieves the data, rather like an FM radio. The further from the exchange, the more of the high frequencies are lost, and the harder to discern the data , effectively lowering the data rate. ADSL2+ doubles the carrier frequency to 2.2MHz. But while that means you can cram more data onto the carrier, the attenuation with distance is greater. So you don't necessarily see a tripling of data speeds everywhere; in fact, at distances above 4.7km, you won't see any difference (see graph).

Around 86% of premises are located within a 5km local loop length from their exchange [in the UK].

In Ireland in some areas a minority may be within 4.5km. Lines may be poor. It's not as crow flies either but route of cable alongside/under road.

I'd love to know real figures for this and for how many see the present increases in Ireland on DSL. Plenty of people seem to be at limit already and even not able to get a full 1Mbps or 3Mbps.

everdead.ie

That's interesting i was under the impression that bt's entire network had been upgraded to 24mb/s already and thats what made speeds in ireland look so abdysmal. I dont understand though why if as the article said vdsl vectored or whatever can get such high speeds why they dont roll that out instead of taking such baby steps. I know that when you get further away from the exchange that the speeds dwindle down but it would be away to maybe gaurantee speeds of 24mb/s.