[WM6]

If target act as radio wave source (in case of reflected radio waves - from using GPR apparatus par example or distance radio station using Gold Gun pistol), ferrite antenna can point to those targets: if from target surface reflected signal is strong enough and suit to radio band to which ferrite antenna is tuned. But, this (reflection from targets) is all in case, if we hunt using radio waves (which incorporate magnetic component too).

When we hunt using changeable magnetic field (as with most metal detectors), there is no reflection of magnetic field from targets surface. Targets in changeable magnetic fields act as many very small oscillatory circuits (as many such minuscule circuits, as many eddy currents was created at target surface) and in consequence metal targets act in changeable magnetic field as load (by changing inductance of coil, frequency of coil tank circuit, or amplitude and phase of oscillation).

Where we have magnetic component: as main one (in case of metal detector) or as part of radiation (in case of radio waves), we can use ferrite antenna: as to wave source pointing direction or as magnetic field concentrating means (two such examples: transistor SW radio, pinpointer).