3.4 Measurement Box Antenna (For 30 MHz or less)A device to measure the radiated noise in the band of 30 MHz or less emitted from the specimen. Since the measuring box is the loop antenna type as shown in Fig. 5, it shall be installed on the nonconductive skid such as a wooden table to carry out measurement. The metallic table must not be used as it will intercept electromagnetic wave, which is penetrating the loop antenna, in such a way as to deteriorate the measuring value which leads to inaccurate measurement.(1) Dimensions: W500D300H200 mm(2) Material: Polystyrene foam or other material having relative permittivity of nearly 1.(3) Antenna: Wind two turns of AV wire or formal wire whose lead wire section is 1 mm diameter around the box.(4) If the box it too small to accommodate the test specimen, the opening area W (mm)D (mm) may be increased. In such a case, however, the test data shall be determined by subtracting the coefficient 20 Log10 [(WD) / (500300)] (dB) from the actual measurement values.