I'm using Unity with Ubuntu 14.04, and there's no manual refresh button for wifi networks that I can find. So when I click on the wifi icon in the upper right, I just have to wait for it to get around to showing me new networks (this is most frustrating when I've just turned on my 4g hot spot). Sometimes I have to wait 15+ seconds to see my hotspot even though my phone and tablet can already see it (so I know the network is available well before Ubuntu sees it).
Is there any way to get a "refresh" option added to the wifi options in the network drop down list, or to decrease the time between scans for open networks?
The best answer might be from here:
Go to the command line and type:
Assuming your wifi is called wlan0 (it might be wlan0 or something else) see ifconfig for details.
This command will refresh the list by asking the wifi to rescan. You can only do this as root and if you do it as non-root it will simply print the list of known networks without refreshing.
Click the WiFi icon on the top menu bar, uncheck "Enable Wifi", this will disable your WiFi. Go back to the top menu and click the WiFi icon and recheck "Enable WiFi" to re-enable your WiFi. The available networks list will automatically repopulate.