Finding the dead spots in your home

Everyone knows the bad corner: the room where calls drop, the desk where a file will not upload. What almost nobody has is a measurement of it, and without one the conversation stays stuck at the level of anecdote. A dead spot survey is not complicated. It needs a live reading, a slow walk, and enough discipline to hold the phone the same way at each point, and it produces something genuinely useful — a picture of where the coverage in your own home actually is, and therefore where the desk should go.

Set up so the numbers are comparable

Decide on one posture and keep it. Hold the phone at chest height, screen toward you, in the same hand, and do not cup the lower edge where the antenna usually sits. Your body absorbs a surprising amount at these frequencies, so turning around at the same spot can change a reading by several decibels; note which way you were facing. Do the walk once with the phone on the network it normally uses, and avoid starting a download while you measure, because traffic changes the picture. If your handset offers a setting to prefer a particular generation, leave it alone: the point is to measure the service you actually get.

Walk it slowly and let the reading settle

Modern chipsets average their measurements over a short window, so a value needs a couple of seconds to catch up after you move. Walk at half your normal pace, stop at each place that matters, and give the number four or five seconds before writing it down. Cover the obvious candidates and a few controls: every room, both sides of the bed, the desk, the kitchen counter, the bathroom, the stairwell, the balcony, and one spot outdoors as a reference for what the network can do at your address when nothing is in the way.

Read the building, not just the phone

Attenuation explains almost everything you will find. A plain interior partition costs a few decibels. A reinforced concrete wall or floor costs a great deal more, and the steel mesh inside is what makes some flats behave like cages. Modern coated glazing is the surprise: the thin metallic layer that keeps heat in also reflects radio, and a whole window wall can be worse than the brickwork beside it. Foil-backed insulation, tiled bathrooms, lift shafts, boiler cupboards and underground parking all show up in a survey as sharp local drops. Once you see the pattern, the low readings stop being mysterious — they line up with the structure.

Draw it rather than list it

A column of numbers is hard to reason about; a path coloured by strength is not. Walking a route while the device records position and signal together produces the shape of the coverage in the space, with the weak stretches visible as a run of colour rather than a single anomalous value. The app this guide belongs to does exactly that: the walk draws your own track, coloured by what was measured along it, and marks places where the reading fell below the usable threshold. No map tiles are downloaded and the track never leaves the device, which matters when the map you are drawing is the inside of your home.

Repeat before you conclude

Do the walk twice, ideally at different times of day. Radio conditions change: the network reconfigures, neighbouring cells load up in the evening, and the specific cell serving you may not be the same one an hour later. Two runs that agree give you a real map. Two runs that disagree wildly tell you something else that is worth knowing — that your position is on the boundary between cells, where the phone keeps changing its mind, which is its own kind of problem and typically shows up as calls that drop on handover rather than as a uniformly weak reading.

Fix what the map shows

If one room is bad and the rest is fine, the cheap answer is furniture: move the desk toward the window wall, or work from the room that measured well. If the entire home reads poorly but outdoors is strong, the building is the problem, and the two effective fixes are Wi-Fi calling over your broadband and an operator-supplied femtocell. If outdoors is also poor, no indoor device will help; that is a coverage gap at your address, and the survey is now evidence you can hand to your operator, who can check whether a different band or a nearby site should be reaching you.