Which type of station may transmit one-way communications?

In amateur radio, communications are generally required to be two-way. However, beacon stations are a specific, regulated exception. Beacons automatically transmit one-way signals to help operators test equipment, study radio wave propagation conditions, and determine if a band is open to different parts of the world. Repeaters, HF stations, and VHF stations are generally used for two-way conversations. While a repeater automatically transmits what it receives, its purpose is to facilitate two-way communication between users, not to originate standalone one-way broadcasts.