A RF transceiver for RF communication with a further RF transceiver is described. The RF transceiver comprises a RF transmitter; a clock generator coupled to the RF transmitter, the clock generator comprising a crystal oscillator circuit including an amplifier, a distance monitor configured to monitor the distance between the RF transceiver and the further RF transceiver; a controller coupled to the distance monitor and the clock generator. The controller is configured to vary the crystal oscillator swing amplitude dependent on the distance between the RF transceiver and the further RF transceiver.