A method is provided for controlling transmission of an electronically steerable antenna system, wherein the electronically steerable antenna system comprises a signal generator configured to generate electromagnetic waveforms, and an antenna. The electronically steerable antenna system is configured for transmitting at least interrogation signals and ISLS control signals, and the method comprises the steps of, when transmitting the ISLS control signals: generating an electromagnetic waveform; applying a first transmission phase offset to the electromagnetic waveform, wherein the first transmission phase offset determines the phase offset between each antenna column pair; applying a second transmission phase offset to each antenna column of the second antenna half, wherein the second transmission phase offset of the second antenna half offset is 180 degrees in relation to the first antenna half; and transmitting the generated electromagnetic waveform whereto the first and the second phase offsets have been applied.