Let's assume that in free space (i.e. in homogeneous nepoglashchayushchy environment which relative dielectric permeability is equal units the isotropic radiator - the imagined dot radiator which is evenly radiating radio waves in all directions is placed.
According to the SanPiN 4/056 - 96 we will accept the following maximum permissible levels (MPL) of intensity of a field E: for f1 and f2 PDU1 = PDU2 = 4 in oil, for f3 and f4 PDU3 = PDU4 = 5 in oil, for f5 - f7 PDU5 = PDU6 = PDU7 = 6 in oil.
Thus, the coefficient of strengthening shows, in how many time needs to be reduced (or to increase) the power brought to the directed antenna in comparison with the power brought to the ideal not directed antenna without loss to receive identical intensity of a field in the considered direction. If does not become special reservations, the strengthening coefficient (as well as coefficient of the directed action) is meant as its maximum value corresponding to the direction of a maximum of the directional pattern.