What Coverage Maps Show
A coverage map represents the predicted geographic area where a mobile signal of a specified minimum strength can be received, based on a radio propagation model. The model inputs include base station locations, antenna configurations, transmission power, and terrain elevation data. Building data may or may not be included, depending on the resolution of the model.
Operator maps are typically generated with planning software (such as Atoll or Forsk) and are updated as new base stations are commissioned or existing ones are reconfigured. They represent a snapshot in time and may not reflect recent infrastructure changes.
Color Coding and Legend
Each operator uses a slightly different color scheme, but common conventions include:
| Color (typical) | Coverage Level | Expected Experience |
|---|---|---|
| Dark blue / Green | Excellent outdoor coverage | Full signal bars, high data throughput |
| Medium blue / Light green | Good outdoor coverage | Reliable voice calls and data |
| Light blue / Yellow | Moderate outdoor coverage | Adequate for voice, variable data speeds |
| No color / White | No predicted coverage | No service expected |
Some operators also offer separate map layers distinguishing between voice coverage (requiring a minimum signal threshold) and data coverage (requiring higher signal quality), as well as separate layers for 2G, 3G, 4G, and 5G technologies.
Outdoor vs Indoor Coverage
Most publicly-accessible coverage maps display outdoor coverage predictions. They represent the signal strength expected at ground level in open-air conditions. Indoor coverage is substantially lower due to building penetration loss — typically 10–30 dB depending on construction materials and building design.
Some operators (particularly Deutsche Telekom) offer a separate indoor coverage layer on their maps, which applies an additional attenuation factor to the outdoor prediction. This indoor layer is less accurate than the outdoor prediction because it cannot account for specific building materials or floor layouts.
Known Limitations of Coverage Maps
- Modeled, not measured: Maps show computed predictions, not field measurements. Actual signal can differ significantly from predictions.
- Static snapshot: Maps do not reflect network congestion, time-of-day variations, or temporary outages.
- Terrain resolution: Propagation models use digital elevation models (DEMs) of varying resolution. Low-resolution models miss valleys, ridgelines, and terrain features that cause local coverage shadows.
- Building database limitations: Not all operators incorporate detailed 3D building databases. Without building data, the model cannot account for urban canyon effects or large building shadows.
- Device sensitivity variation: Coverage predictions assume a reference device sensitivity. Modern flagship phones typically have better antenna performance than budget devices, which can receive a usable signal at lower levels than predicted coverage thresholds.
Coverage Check Tools in Germany
Each German MNO provides an official online coverage map:
- Deutsche Telekom — Netzausbau
- Available at telekom.de/netz. Offers layers for voice, data, 4G, and 5G coverage with an optional indoor coverage toggle.
- Vodafone Germany — Netzabdeckung
- Available at vodafone.de/hilfe/netzabdeckung.html. Shows 4G and 5G coverage with address search functionality.
- O2 (Telefónica) — Netzabdeckung
- Available at o2online.de/service/netz-verfuegbarkeit. Provides technology-specific layers including voice and data.
The Bundesnetzagentur Breitbandatlas (broadband atlas) provides an independent view of coverage data submitted by all operators, allowing cross-operator comparison at a given address.
Bundesnetzagentur Coverage Atlas
The Federal Network Agency (Bundesnetzagentur) maintains the official Breitbandatlas at breitbandatlas.de. Operators are legally required to submit coverage data to this tool as part of their spectrum license conditions.
The atlas allows users to check predicted coverage at a specific address across all three operators simultaneously. It also includes data for previous years, enabling comparison of coverage improvement over time. The data is published with a 6–12 month lag relative to actual network state.
Frequently Asked Questions
Why does the map show coverage but I have no signal?
Coverage maps are predictions based on models. Local terrain, buildings, temporary obstacles, or base station maintenance can all cause signal absence in areas the map predicts as covered. If discrepancies persist, report them through the operator's feedback mechanism or the Bundesnetzagentur Funkloch-App.
Are coverage maps legally binding?
No. Coverage maps are informational tools, not service guarantees. Operators publish them to help customers make informed choices, but coverage predictions carry no contractual obligation to provide service at a specific location.
How often are operator coverage maps updated?
Update frequency varies by operator and map type. Major coverage map refreshes typically occur quarterly or when significant infrastructure changes are made. Check the "last updated" date shown on the operator's map interface, as some tools display this information.