A quiteÂ embarrassingÂ fact, both for me as a geek and for Android 2.3 and probably other versions, or maybe the low hardware quality of some phones. I could not find my wifi, but all I had to do was to switch the channel of my wifi to a lower number. It was on channel 12, switched to channel 1 and my phone could find it.
My router configuration now:
Channel: 1 (instead of 12)
Linux; U; Android 2.3.5; en-us; Huawei-U8652 Build/HuaweiU8652B855)
Fixed! (looking forward to a more up to date smartphone.)