The direction of the emitter is identical to the direction of the radio wave incidence only in the event of undisturbed wave propagation. Usually, a large number of partial waves arrive from different directions, creating a more or less scattered field. The direction finder takes spatial and temporal samples from this wave front and estimates azimuth and elevation values for the most probable direction of the emitter.

Understanding the factors that influence direction finding is important. This includes basic knowledge of signal reflection and polarization. Of course, DF accuracy and DF sensitivity are also vital performance parameters. DF site selection and DF correction possibilities also need to be considered.