Transpondrer

A transponder is an electronic device that receives a radio signal or acoustic signal and, in response, automatically transmits a second signal. The term is a portmanteau of transmitter and responder. Transponders are commonly used in various applications, including aviation, maritime navigation, and space exploration.

In aviation, transponders are crucial for air traffic control. Aircraft are equipped with transponders that, when interrogated by radar from the ground, reply with a code. This code, often referred to as a "squawk code," identifies the aircraft and provides information about its flight, such as its altitude and origin. This allows air traffic controllers to track and manage aircraft safely and efficiently.

Maritime transponders, often called radar transponders or SARTs (Search and Rescue Transponders), are used for locating vessels in distress. When activated, a SART will transmit a distinctive radar signature that is visible on nearby radar screens, aiding rescue efforts.

In space, transponders are used for communication between spacecraft and ground stations. They relay data, commands, and telemetry information. The complexity and functionality of space transponders can vary greatly depending on the mission requirements.

The fundamental principle behind a transponder is its ability to respond to a specific stimulus. This response is typically an amplified and retransmitted signal, often on a different frequency or with additional information encoded within it. This makes them invaluable tools for identification, tracking, and communication across diverse technological fields.