MacBook Air: Can't connect to my TP-Link wifi router
After long experimenting I've changed my Wi-Fi channel settings on the router from "Automatic" to an average value (8, in the range 1 - 13). 

Now the network is well visible.

Ed. Here: https://apple.stackexchange.com/a/74575/36329 is shown how to check what channels are supported by Apple (Broadcom actually) hardware.