What is a satellite beacon?

A satellite beacon is a continuous or periodic one-way transmission sent by the satellite down to Earth. It typically carries telemetry data, which provides essential status information about the satellite's health, such as battery voltage, solar panel output, and internal temperatures. Beacons are incredibly useful for amateur operators on the ground. By tuning to the beacon's frequency, an operator can determine exactly when the satellite comes into range. Listening to the beacon also allows operators to gauge the effects of Doppler shift on the received signal, helping them calibrate their receiving equipment before attempting a two-way contact.