Many posters have problems hooking up to WiFi. Distance often is part of the problem. But also what is in that distance. I read posts about someone cannot hook up although they are only 6 feet from their router. Then several posts later they write that 6 feet includes an interior wall, a hallway, an exterior wall (composed of drywall, insulation, and aluminum siding).
Those walls attenuate the signal a lot more than 6 foot of clear air across the living room.
/edit - (thanks to DreadPirateRush)
For the 2.4GHz camera wi-fi a “wi-fi analyzer” app will give you a good idea of signal strength.
However with the Sense it operates on 915MHz, and I have not found a free Android app to measure that signal strength,