Intermittent internet loss

Internet frequently goes out.  Will drop calls on VOIP line almost assuredly sometime during a 30 minute conversation.  Computer stops being connected to internet as well even though WiFi signal remains good.  I will be working on a site and go away from computer for a little bit and when I try to do something, internet is not connected.  Wifi shows good signal throughout loss.  Opening new sites seems to speed internet return.  Refreshing/reloading site does not seem to help.  Eventually internet returns, but it is quite annoying.