I used a tape measure and a mobile wifi sweetspot application to create a heat map of my home’s wifi coverage, after noticing significant reduction in performance in my kitchen. The subjective experience was confirmed through measurements.
I created this grid of our apartment using a tape measure and measured the wifi intensity in each grid using a wifi sweetspot app. The heat map indicates, that the kitchen (top left) has a significantly poorer coverage, than the rest of the floor. Causes are probably the freezer and refrigerator (light grey in the picture) between the basestation (top right) and the kitchen itself.
The thicker line is a floor separation, the center light grey box represents the stairs. The dark grey areas are either cabinets or other heavy immovable objects (tables, fireplaces etc.) I didn’t measure the yellow areas.