Default WiFi hotspot keeps disconnecting

I'm having problems on my Z1 C6902 the wifi hotspot always disconnects and i have to turn off and then on the wifi hotspot again for the PC to be able to find the network again to connect. It disconnects at random intervals not always at a given specific time and I made sure to check the settings to keep the tethering always on.
Thought it was a firmware problem but it's the same after updating it to 4.4 from 4.3 (stock firmware).
any one has the same problem and found a solution?

Sony XPERIA Z2 D6503