Abstract: The invention relates to a device at antenna systems for generating radio waves, including a supporting structure mounting at least one main radiator (3) for transmitting radio waves and where high frequency electric currents are generated in the supporting structure when the main radiator (3) is transmitting the radio waves. In order to improve the range of the main radiator (3) and at the same time reduce its backward radiation, the supporting structure includes a secondary radiator (14) for each main radiator (3). The secondary radiator (14) has at least one break portion (12) for interrupting or breaking the high frequency currents generated therein and through the thereby interrupted flow of the high frequency currents in the supporting structure reduce deviations from the desired range and/or direction of the radio waves transmitted by the main radiator (3).