Wifi Oddity

An Eccentric Anomaly: Ed Davies's Blog

The other day I built a Nanode so needed to re-jig my network wiring to be able to test it conveniently on the workbench in my office. In the process I needed to reset my Wifi router (forgot the admin password - oops). After that I found my laptop was horribly slow communicating with the big wide Internet.

Later I found that communications from penelope the Pogoplug were slow, too, and hence the problem was with my local network. File transfers across Wifi from the Pogoplug were happening at about 15 kilobits/second or even less. Transfers in the opposite direction were going at a reasonably respectable number of megabits per second.

(I've a wired LAN downstairs on my ADSL modem/router with the Pogoplug and a EdiMax 3G-6200nL NATing a separate Wifi subnet for my laptop.)

My first thought was that it was an MTU problem but messing with those settings didn't seem to help. A lot of Googling found possible problems with Ubuntu Wifi drivers but none seemed to fit exactly. I tried all the "getting out of the car and getting back in again" approaches: rebooting and resetting different combinations.

One off-hand hint on some web page I came across in the process (sorry, forgotten which; it took a while for me to begin to take the idea seriously) suggested changing Wifi channels. The channels shouldn't matter; particularly not in an area where there are only a couple of occupied houses within a kilometre or so and the closest about 100 metres away.

Anyway, I changed the Wifi router from channel 11 to channel 6 and I can now happily transfer about 2 megabytes per second, about 1000 times faster than the 15 kilobits per second I was getting before.

Weird. Needs more investigation but worth remembering for future reference.