Phase directional antenna array and phased ring combiner for radio direction finding

A radio direction finding system for determining the relative bearing angle .theta. of an incoming signal comprising a circular array of an even number of vertical dipoles arranged in diametrically opposed pairs equally spaced apart around the array, each dipole pair having an output feeding two branches, one branch electrically advancing the phase of a signal from each dipole pair by an amount equivalent to the angular displacement in one direction of each dipole pair with respect to a reference direction established by a reference dipole pair and the other branch retarding the phase of a signal from each dipole pair by an amount equivalent to said angular displacement, means for combining all the phase advanced signals to form a signal voltage V.sub.d which is retarded in phase by an angle .theta. corresponding to said relative bearing, means for combining all the phase retarded signals to form a signal voltage V.sub.s which is advanced in phase by said angle .theta., and means for measuring the phase difference (2.theta.) between V.sub.d and V.sub.s whereby .theta. is obtainable by dividing said phase difference by 2.