Really basic wireless survey with built-in linux tools

What channel should I use for my access point? It seems like I'm always asking this question as people start new access points in my neighbourhood. Some wireless access points can pick a channel automatically, but my experience with this has been pretty poor. I suspect the algorithm is too simplistic to be of any use. A naive implementation might pick the first channel that has no other APs on it, which could be a terrible choice if the strongest interference signal is on the adjacent channel.

Ideally you want to pick the channel that gives you the best signal-to-noise ratio, but where there are heaps of APs at varying strengths in different parts of the house the choice is non-obvious. Sadly there doesn't seem to be a FOSS wireless survey tool like Fluke AirMagnet, and while you can use kismet to collect signal strength data you will have to do some analysis of the data yourself (my wireless card also didn't play well with kismet).

I decided to optimise for one location - where I use the laptop the most. So I set my AP to channel 1 and:

sudo iwlist wlan0 scanning > ch1.txt

Rinse and repeat for all the other channels (setting the channel on my AP is quick, but this might be impractical if yours is slow, requires re-auth etc.). Then compare the signal strengths:

grep --before-context=4 "myessid" ch*.txt

Pick the channel with the highest quality number (best signal strength).