Signal quality California Mobile Signal Quality Map Where mobile service in California is slow, and why. Wherobots joined Ookla speed tests with towers, terrain and tree canopy to separate slow areas with a clear line of sight to a tower, a capacity problem, from areas where hills or trees block the signal. Open the full map Talk to our team 2,854 slow areas within 2 km of a tower 79.9% of those have a clear line of sight 1.51M people in capacity-limited areas Los Angeles basin, California Share of measured service that is underserved under 10% 10-25% 25-50% 50-75% 75% or more not measured Of 2,854 slow areas within 2 km of a tower, 2,281 (79.9%) have a clear line of sight: a capacity problem. Speed tests: Ookla Open Data. Towers and buildings: Overture Maps. Terrain: Copernicus. Canopy: Meta. Population: US Census ACS. Analysis: Wherobots. Basemap: OpenFreeMap, OpenMapTiles, OpenStreetMap contributors. How the map is built Measure service Ookla speed tests cover 48,999 map tiles and 231,828 tests across California. 6,664 of those tiles (13.6%) are underserved. Find the nearest tower Slow areas within 2 km of an Overture Maps tower are the near-tower set, where tower distance does not explain the slow service. Check the line of sight A modeled sightline over terrain and tree canopy splits slow areas into capacity-limited, terrain-blocked and foliage-blocked. Count the people US Census ACS estimates give the population of each kind of slow area. Capacity-limited areas hold 1.51 million people. FAQ California signal quality map FAQ Why is most bad service a capacity problem? Of the 2,854 slow areas within 2 km of a tower, 2,281 (79.9%) have a clear line of sight to it. The signal reaches them, so the limit is network capacity. Why are many hexagons grey? Only 8,872 of the 78,109 hexagons have a speed test. Grey means not measured, never zero, so every underserved count on the map is a floor. Is the line-of-sight check a speed prediction? No. It is a modeled sightline screen over terrain and tree canopy that sorts slow areas by likely cause. Where does the data come from? Ookla Open Data speed tests, Overture Maps towers and buildings, Copernicus terrain, Meta canopy height and US Census ACS population estimates. What did Wherobots compute? Wherobots joined the speed tests to the nearest towers, ran the line-of-sight checks over terrain and canopy, and counted the people in each slow area. Find your capacity gaps Tell us about your network, and we will walk you through the analysis on your markets. Talk to our team
