Abstract: Pulse radar apparatus comprising at least an error voltage generator, a dither-tuned magnetron, a frequency control circuit, a conditional circuit and an angular position indicator connected to the magnetron tuning shaft for turning the local oscillator frequency f.sub.l to a frequency f.sub.lo, showing a fixed difference f.sub.o with the magnetron frequency, where f.sub.o = f.sub.z - f.sub.lo. When, by means of the indicator, the conditional circuit determines that the magnetron is being tuned in a defined frequency range comprising the frequency f.sub.l, the frequency control circuit is alternatively supplied with an error voltage and a voltage proportional to ##EQU1## TO DELIVER A FINE AND A COARSE TUNING VOLTAGE, RESPECTIVELY.