Why is one of my WiFi networks not visible after connecting to the other one? I've got two access points / WiFi networks at my home and there is a strange behavior with my Android 4.0 phone (SGS2): after my phone connects to one network or the other (whichever is currently stronger), the other network becomes invisible. It cannot be found in this list of currently available networks in the system menu, it is not visible in apps like Wifi Analyzer etc.

After I turn off the WiFi and turn it on again, both networks are visible again. Then I connect to one of them and after a while, the same repeats again - the other network becomes completely invisible.

What could be causing this? It is a problem for me because apps like Best WiFi then cannot work properly.
How many other APs (Access Points) and devices are their in the vicinity?

If your first AP (on channel X) is causing overloading (or interference) on that channel, other APs are going to change signal strength and/or change to other channels.

Basically, you are dropping a large pebble into a small pond.  There is always going to be other effects.

If this happened under controlled conditions (i.e. out in the country), with no other signal sources or traffic, then you would have a legitimate puzzle ..