How come Android finds lists Wi-Fi networks that OS X doesn't? I have a MacBook Air with OS X 10.8.5 and a Samsung cell phone with Android. I use the Wi-Fi heavily on both (I travel a lot, and only use Wi-Fi when I'm out of the US) — often in cafes — and I rarely ever have a problem. Wi-Fi is usually perfect and easy in any cafe.

But there are a couple of cafes I frequent where, my Samsung Android phone picks up the cafe's Wi-Fi signal — and picks it up very strongly — but on OS X, the network just doesn't list it at all. I know it's not a signal-strength issue, since on the Samsung Android, the signal is super strong in all 3 cafes. But OS X for some reason just doesn't find the network — not even when I go to "Join other network" and type in the network name.

What could cause this? …and is there a solution to this that you would recommend?
1) Possible interferences :

Do you have many Bluetooth peripherals connected to the Mac ?
Try tuning off Bluetooth and connecting to Wi-Fi…
http://support.apple.com/kb/HT1365 

2) Possible mal-functionning hardware :

Check your machine is working with extra channels than 1 to 13 (802.11g) by going in the "Apple" menu, hold down the "alt" key and select "System Information…".

Then in the "System Report…" window select in the sidebar "Wi-Fi" or "Airport" under "Network".

You should see next to :

"Supported PHY Modes" : 802.11 a/b/g/n

"Supported Channels" : 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 36, 40, 44, 48, 52, 56, 60, 64, 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140

If this is not ok you might need to have your machine serviced as every MacBook Air are compatible with 802.11n. Beware that some channels are banned in some countried thus restricted on your machine : http://en.wikipedia.org/wiki/List_of_WLAN_channels

3) Possible problem with the configuration of the router :

I have encountered sometimes connection drop / timeout with 300 Mbps optimisation (using wide channel configuration 2,4GHz and 5GHz : 20 MHz and 5GHz only : 40 MHz) and some computers. Best would be if the cafes you go to could make sure to have an optimised network for everyone.


If the newtork requires a password : WPA / WPA2 encryption instead of WEP ;
Support for both channels (if using 40MHz with 2,4GHz channels can create performance and reliability issues) ;
For a cafe IP addresses should be cleaned regulary (leased time 1 hour) ;


http://support.apple.com/kb/ht4199