The phase and frequency commands of a ratating radar system that utilizes frequency scanning to steer the beam in the azimuth direction and phase shifters in the elevation direction are derived in terms of the angles of the groung based coordinate system. The antenna type considered is slotted arrays that are easy to construct at such high microwave frequency as the X band. The frequency that has non-linear characteristics as a functio ofthe elevation angle is plotted and the derived frequency equation is aproximated to be a simple form to reduce the calculation time for real time multi-function radar systems. It is shown that the approximated frequency command is in good agreement with the exact one if the range of azimuth scanning is limited by ${pm}10^{circ}$.