What is a normal range for these to work? Mine is about 20' away from the controller, with one brick wall between, and I get a "No signal" light every day. If I press the top a few times, it resets, but comes back the next day. I figured it has at least the normal Wi-Fi range of 300', no obstacles, and should be ok at 20' thru the exterior wall. Any opinions? Oh, and I replaced the batteries yesterday.