Method for transmitting data, in particular sensor data, by radio between at least one node, which is preferably installed permanently at a fixed location, and a base station in a communication system having a unidirectional or bidirectional radio transmission mode, wherein the base station comprises a communication module having a first frequency transmitter, wherein the node comprises a communication module having a first frequency transmitter and a second frequency transmitter with a lower frequency than that of the first frequency transmitter, wherein the communication module of the node is intended to use radio telegrams to transmit data to the communication module of the base station by means of data packets, wherein a carrier frequency is generated for the transmission of the data packets by the first frequency transmitter, wherein the first communication module of the base station a reception window is temporarily opened to receive the data packets, wherein the first communication module of the base station is intended to receive the data packets from the communication module of the node within the reception window, and wherein a calibration is performed between the frequency of the first frequency transmitter and that of the second frequency transmitter of the node, wherein the base station expects the data packets from the node on the carrier frequency, to this end the base station uses the received data packets to estimate the carrier frequency and uses this to determine the variance between the frequency of the first frequency transmitter of the node and the frequency of the first frequency transmitter of the base station, the base station moreover continually stores the variance between the frequency of the first frequency transmitter of the node and the frequency of the first frequency transmitter of the base station, and a calibration is performed between the frequency of the first frequency transmitter of the node and the frequency of the first frequency transmitter of the base station. wherein the base station comprises a communication module having a first frequency transmitter, wherein the node comprises a communication module having a first frequency transmitter and a second frequency transmitter with a lower frequency than that of the first frequency transmitter, wherein the communication module of the node is intended to use radio telegrams to transmit data to the communication module of the base station by means of data packets, wherein a carrier frequency is generated for the transmission of the data packets by the first frequency transmitter, wherein the first communication module of the base station a reception window is temporarily opened to receive the data packets, wherein the first communication module of the base station is intended to receive the data packets from the communication module of the node within the reception window, and wherein a calibration is performed between the frequency of the first frequency transmitter and that of the second frequency transmitter of the node, wherein the base station expects the data packets from the node on the carrier frequency, to this end the base station uses the received data packets to estimate the carrier frequency and uses this to determine the variance between the frequency of the first frequency transmitter of the node and the frequency of the first frequency transmitter of the base station, the base station moreover continually stores the variance between the frequency of the first frequency transmitter of the node and the frequency of the first frequency transmitter of the base station, and a calibration is performed between the frequency of the first frequency transmitter of the node and the frequency of the first frequency transmitter of the base station.