Abstract: A method for synchronizing transmissions of mobile stations in a mobile radio system including a first and second mobile station and a radio unit all communicating on a direct mode channel. According to the method, the radio unit transmits synchronization information messages on the direct mode channel, which messages indicate the frequency used by the radio unit, and which messages include accuracy information, indicating that the accuracy of the transmit frequency used by the radio unit exceeds the accuracy normally employed on a direct mode channel. The mobile stations receive the synchronization information messages and tune respective receivers and transmitters to the frequencies indicated by the synchronization information message.