The sensor behaved perfectly on the dinette. A reading every few seconds, battery full, nothing to argue with. Then you carried it to the back bedroom, stuck it on the wall above the nightstand, walked up to the front of the rig and watched it go quiet.
Nothing is broken and nothing needs sending back. What changed between the dinette and the bedroom is about twenty feet of trailer, and a trailer is built from the two materials 2.4 GHz radio copes with worst. Bluetooth Low Energy is quoted at about 30 feet in open space, and open space means open air with nothing in the way. Through metal and water you get a good deal less.
Metal, water, and the fridge in the middle
Aluminium siding and framing do not absorb the signal so much as bounce it. A wave that meets the sidewall gets sent somewhere else, so it reaches the hub by a longer path or it does not reach it at all, which is why nudging a sensor six inches sometimes fixes everything and sometimes changes nothing whatsoever.
The refrigerator is the obstacle nobody predicts. It is a large insulated metal box, and in most floorplans it sits in the middle of the rig, directly on the line between a hub at the front and a sensor at the back. Water tanks do the same work in their own way. Water absorbs at this frequency, so a full tank blocks more than an empty one, which gives you the genuinely odd symptom of a sensor that reports happily on the way to the dump station and drops out on the way home. A shut cabinet door adds one more wall you were not counting.
In practice a 25 foot travel trailer is usually fine on one hub. A 40 foot fifth wheel with a slide and the fridge halfway down it often is not, and the first thing to try about that costs nothing.
Move the hub before you buy anything
The hub tends to end up at the front, near the entertainment centre, because that is where the outlet and the router already are. It is the worst seat in the house: one end of a metal tube, with the fridge parked in the middle of the only path that matters. Put it on a central outlet instead, out of the cabinet, at roughly waist height, and it will usually hear both ends of the rig at once, which fixes more range complaints than everything else on this page put together.
Try this first: leave the sensor where you want it and walk the hub around the rig on an extension lead, watching which positions bring the readings back. Ten minutes, no money, and a great deal better than guessing.
When one hub genuinely is not enough
Some rigs are simply too long, and once the extension lead has proved it, the answer is a second hub down at the far end. Hub count is not metered on your plan, so the second one costs you the hardware and nothing after that. Charging somebody more every month because their fifth wheel is long is a strange way to treat a customer who has already bought the equipment.
Nothing you plug in will fix this
The Wi-Fi extender in the drawer is the first thing most people reach for, and it does nothing here at all. Different radio, different job: it extends the link between your router and your laptop and takes no part in the Bluetooth conversation between a sensor and a hub. Generic Bluetooth repeaters are usually the next purchase and they are no better, because BLE advertisement traffic is not something a consumer repeater usefully relays.
A fresh battery deserves thirty seconds of consideration and no more of your afternoon. Transmit power does not meaningfully rise with a new cell, so if the sensor is reporting at all, whatever is wrong is not the battery.
How much silence is normal
A sensor at the edge of range does not fail cleanly, it frays. It reports, misses a handful of broadcasts, reports again, and somebody walking down the hallway can be the whole difference. So nothing should be alerting you on a single missed reading. On a sensor that broadcasts continuously, a gap of a few minutes is radio noise rather than an event, while a gap of an hour is a sensor that has genuinely gone, and that one has earned the right to wake you up.
If a sensor lives permanently at that edge, do not get used to it. Move the sensor, move the hub, or add the second one, because a reading you cannot trust to arrive is not worth much: sooner or later you stop checking it, and then you are not checking the good ones either.
The sensor on the dinette was never lying to you. It simply had nothing in the way.
