1. 802.11n in its 40MHz OFDM has one non overlapping channel. So if you have two routers set to 802.11n you may have troubles. Fix? Set them to 20MHz OFDM or just go to 802.11g.
2. Any Android phone can use "WiFi Analyzer" for free to see a quick view of channels.
I use it a lot.
3. My 4 year old router began to lock up and with that, drops so I replaced the router. All better. I've seen folk with failing routers spend months "diagnosing" or worse, paying techs to try to fix it. Most paid more than what the new router cost.
4. Walls and distance. If you are having issues, drop the distance by half.
The one that Windows offers is now $19.99, and after downloading "Acrylic" I got an error message that it doesn't work on my brand new Asus laptop....so what is a free wifi router channel analyzing program that is widely used?
On a side note, I don't actually know if this will solve my problem. I'm in a two story house in a completely rural area that is actually 2 separate apartments. The router and all that has to stay downstairs (I stay upstairs), but over a one year period the wi-fi has gotten worse and worse, with signals dropping randomly and frequently from all wireless devices (even the ones downstairs) including the Wii, from which watching Netflix from has become impossible due to the number of interruptions in signal (like every 20 seconds?) If anyone has any suggestions here, I would love to hear them!