"The System of 4 combined antennas YAGI 16, was designed to achieve a higher gain and more efficient directivity, under the conditions of uniform electromagnetic field (homogeneous). Uniform homogeneous field occurs when receiving signal from very distant stations. To achieve the declared gain, deviations of heterogeneity field in the area of antenna dimensions may not exceed 0.5 dB. Narrow beamwidth in the vertical and horizontal, helps to eliminate (weakness do about -30 dB) unwanted signals, located in a short angular distance of  >12 °  from main beam.