An apparatus including a leaky feeder arrangement including a plurality of parallel leaky feeders, a transmitter coupled to the leaky feeder arrangement and configured to supply individual first radar signals to a group of leaky feeders in the leaky feeder arrangement, the first radar signals being configured to form a first radar signal beam in a predetermined direction relative to the leaky feeder arrangement, a receiver coupled to the leaky feeder arrangement and configured to receive a second radar signal from the leaky feeder arrangement, wherein the second radar signal is reflected from the target object when the first radar signal beam hits the target object, and a processing unit configured to analyse a first signal corresponding to the first radar signals and a second signal corresponding to the second radar signal to determine the properties of the moving object. A wind turbine and a method are also provided.