Protection distance for HF communication based on emission standards

The fast development of new types of energy-smart products has made the regulation of electromagnetic compatibility (EMC) falling behind for some areas. Examples of such techniques are solar plants, wireless power transfer for stationary charging of electric vehicles and electric roads. These kinds of installations might generate electromagnetic interference that can interfere with communication systems. To protect the communication system, protection distances around communication receivers need to be introduced.In this work, the necessary protection distance is determined for the high frequency (HF) band 1.6-30 MHz. The potential interference source is assumed to fulfil a certain emission standard limit, such as CISPR 11, EN 50121-2/IEC 62236-2 and IEC 61980. Since HF radios are noise constrained, the protection distance is derived in comparison with the ITU interference category Rural. For the analysis, two different field propagation models for ground wave propagation for HF signals have been evaluated.It is concluded that the investigated ITU model is suitable as a model for the field propagation of the ground wave. The longest protection distance is about 10 km, but the variation is large for different EMC standards, ranging from a couple of hundred meters. The choice of Class A or B levels has a large influence on the protection distance.