Ofcom publishes sync speed data (18.2MB zipped) for each postcode where they have data for three or more lines. These account for 1.7 million connections in Scotland.
Here we aggregate median speed data for Scotland to show the distribution of median speeds for postcodes at different distances from their exchange. The area of each circle is proportional to the number of connections.
We see clearly that many postcodes have a median speed of < 2 Mb/s. In fact, these postcodes account for 54,750 connections, mainly more than 2 km from their exchange.
Median speeds above 30 Mb/s (superfast speeds) are reported as 30. Almost 100,000 connections fall in superfast postcodes, mainly within 2 km of their exchange.
We also see that ADSL ('up to' 8 Mb/s) reliably provides this advertised speed for most postcodes within 1 km of the exchange, most postcodes beyond 2 km from the exchange have slower median speeds.
Similarly, the ADSL2 ('up to' 24 Mb/s) service provides no advantage for those further than 2 km from the exchange, and median speeds above 20 Mb/s are only seen within 1 km of the exchange.
The teardrops at 20, 25, and 30 Mb/s include most Virgin customers on DOCIS services, and the last of these includes all those currently benefitting from NGA. The teardrop shapes show that these speeds are mainly available in postcodes within a 2 km of their exchange – but sometimes Virgin reaches communities further from the exchange.
The worry is that those who were too far from the exchange to benefit from ADSL2, and are not served by Virgin, will again be left behind by NGA.
Michael Fourman, 2013-11-05