When the WiFi "drops" can you still see the wifi name? The wireless network you connect to is something like "VM1234567" Also when it "drops" what are the lights doing on the front of the hub? Compare the lights to what you normally see.
If the wifi name is still present but you cant connect to the Internet its possible the issue is not the wifi but the internet connection. If the Green lights and the phone lights are flickering it could be that the Hub has reloaded.
update this post with your observations
thanks KK