A Wi-Fi dead zone is a part of your home where the signal is too weak to use, and the right fix depends on what's causing it and how your home is laid out. Dead zones show up as slow speeds, lag, and dropped calls in one or two rooms while the rest of your home works fine. Your video call freezes in the back bedroom, or a show buffers in the basement. Where your router sits is a common cause, so moving it is often a good, free first step. Several causes often combine to create dead zones: router placement, distance, thick walls and floors, interference, and an outdated or provider-supplied...