Abstract: Dual mode log periodic dipole antenna apparatus which provides for sum and difference radiation patterns depending on the method of excitation. The antenna incorporates a support structure which secures a plurality of radiators having three elements with successively incresing length. The center and right dipole elements of each radiator and the center and left elements of each radiator are alternately coupled together by separate transmission lines in a crisscross fashion. Input ports coupled to the smallest radiator and driven with a conventional hybrid coupler with either in-phase or out-of-phase energy at either .lambda./2 or .lambda.. Sum and difference radiation patterns are achieved by appropriate selection of the excitation phase. Thus, this antenna may be employed in monopulse or direction finding applications. An alternative embodiment is disclosed which employs center radiator elements offset from the right and left elements of their respective radiators.