Wifi disconnects every few minutes. Overall weak signal . Disabling network, enabling it causes all networks to disappear. Then "connect to hidden network" will show the dropped network , and reconnect is made possible again. This has been reported as a question on Launchpad: https://answers.launchpad.net/ubuntu/+question/266033

upstream kernel 4.2.0-040200rc3-generic;
  *-network
       description: Wireless interface
       product: RT3290 Wireless 802.11n 1T/1R PCIe
       vendor: Ralink corp.
       physical id: 0
       bus info: pci@0000:03:00.0
       logical name: wlan0
       version: 00
       serial: b0:10:41:a5:38:3b
       width: 32 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=rt2800pci driverversion=4.2.0-040200rc3-generic firmware=0.37 ip=192.168.0.103 latency=0 link=yes multicast=yes wireless=IEEE 802.11bgn
       resources: irq:19 memory:f7c10000-f7c1ffff