A wind turbine control master unit has a communication interface and a signal processing unit. The communication interface is configured to receive a rotor rotational speed of at least a first and a second wind turbine over a communication link. The signal processing unit is configured to determine a synchronized rotor speed value based on a mean value of the rotor rotational speeds. The signal processing unit is configured to calculate a synchronized azimuth angle value based on integrating the synchronized rotor speed value. Further, the communication interface is configured to send the synchronized rotor speed value and the synchronized azimuth angle value over a communication link. Also, a signal light control module and a wind turbine in connection with the control master unit are provided.