In examples, Radio Frequency nodes of an array are synchronized using Time-Reversal. A Master node (“Master”) of the array receives and captures a sounding signal emitted by a Slave node (“Slave”) of the array, downconverts it to baseband, Time-Reverses the downconverted signal, upconverts the Time-Reversed signal to the carrier frequency using the Master's clock so that the upconverted signal has phase property of the Master's clock, and transmits the resulting signal to the Slave. The Slave receives the signal from the Master, and adjusts the phase of the Slave's clock so that the phases of the two nodes are aligned. Once phases, frequencies, and time references of the array's nodes are aligned, the array may be used for coherent operation. In examples, the array is used to transmit Time-Reversed signals so that the signals from the array's nodes are spatially and temporally focused on a target.