How to read a coverage map honestly
Carrier maps are marketing documents. Here is how to extract the signal from them — literally.
Every carrier publishes a coverage map, and every coverage map is generated by the marketing department from a propagation model, not from measurements. That does not make them useless. It makes them a document you have to read carefully.
What the colours mean
The shaded area usually answers: "would a device outdoors, at chest height, with clear line of sight, register a usable signal here?" Note the three qualifiers. Your kitchen satisfies none of them.
| Map says | Realistically means |
|---|---|
| Excellent | Works indoors, most rooms |
| Good | Works outdoors; near a window indoors |
| Fair | Calls yes, data unreliable |
The band matters more than the bars
A phone showing full bars on a high-frequency band behind a brick wall will perform worse than two bars on a low band. Bars measure received power; they say nothing about how much of that band's capacity you are sharing with everyone else on the same tower.
Better than the map
Ask a neighbour. Genuinely — one person who lives on your street with the same carrier is worth more than any published map, because they are testing the exact building, the exact walls, and the exact tower load that you will be testing.