Wireless LAN in London

This is a map I built up over a few runs back in 2001. Each red triangle represents a Wireless LAN Access Point, sometimes multiple AP's appear as a single red triangle if they are very close to each other. Some of these AP's broadcast a few hundred metres but due to London being pretty built up, they are usually only good for around 50-75 meters with my omni-directional low gain antenna. You may notice from the map however that a few AP's go straight over the Thames with no problems at all. Clear line of sight and all that.

This is the result of running a few roads and is likely to represent no more than 5% of the wireless networks in central London. Since most of the runs were on sunday afternoons I am assuming that these networks are permenant/semi-permenant as most of the businesses where these networks may reside would have been closed.

click for a larger version (~100 kb)

WEP usage is currently around 35% (Jan 2002.) No attempts were made to associate with these networks so further data is not available.

Equipment used included : Netstumbler software, Thinkpad Laptop, Elsa (Lucent) AirLancer PCMCIA card, Elsa range extender antenna (~ 2.5 dBi gain), Garmin Etrex GPS.

NOTE: I did this again late 2003 using Kismet, the same laptop/card/gps and a REAL 5dbi magmount. It is now very difficult to find somewhere in London where there is no WLAN of some kind detectable even with a modest antenna. One day I may get round to posting the new map.