At what altitude do phones stop working?

Understanding Why Phones Stop Working at High Altitudes

Mobile phones rely on cellular networks to communicate, which consist of ground-based cell towers that transmit signals to and from devices. These signals have a limited range, and their effectiveness diminishes as the distance from the towers increases.

Altitude and Signal Strength

As an aircraft ascends, the distance from cell towers on the ground increases rapidly. Above approximately 10,000 feet, the signal strength from these towers becomes unreliable. The higher the altitude, the weaker the signal becomes, eventually becoming undetectable amidst background noise.

Faraday Cage Effect

In addition to distance, the metal structure of an aircraft acts as a Faraday cage, which blocks electromagnetic signals from entering or exiting. This further inhibits signal transmission between the phone and cell towers.

Consequences and Alternatives

Due to the unreliable signal at high altitudes, phone calls, text messages, and data access become impractical. To stay connected during flights, passengers can consider using in-flight Wi-Fi services provided by some airlines. However, these services are typically收费, and their availability and reliability can vary depending on the airline and flight route.

Conclusion

The combination of distance from cell towers and the Faraday cage effect of aircraft metal structures limits the functionality of mobile phones at high altitudes. Understanding these factors helps passengers anticipate the loss of connectivity and make informed decisions about communication options during flights.