Troubleshoot competing access points and clogged Wi-Fi channels with inSSIDer from metageek.
After setting up my friend’s wireless router she was complaining about slow Internet response. A quick check with inSSIDer from metageek (http://www.metageek.net/products/inssider/) found that it was conflicting with many of the routers in the apartment building next door and the adjacent office building. These were mainly on channels 8 or 11 and while her router had its channel set to AUTO it was also using channel 8. Changing this to channel 2 fixed the problem. So much for AUTO.
While I was checking out inSSIDer (previously I had used NetStumbler), I looked at my own home set-up. My router was set to channel 2 since no one was using it at the time, however now someone very close (the apartment above?) was using channel 3 which in my lounge room was 20db stronger than my signal. Changing my router to channel 8 (which was being used but was 30db weaker than my signal) improved my reception considerably and I now had a good signal on my balcony when previously it was out of range.
So the moral of the story is regularly check what is going on around you because things can change.