Radio waves propagate on the clam ocean surface

High Frequencies (HF) is widely used in navigation wireless communication system. In this paper, we research the energy loss of HF propagating on clam sea. We divided it into three parts, namely, Loss by sea surface reflection, ionospheric losses and losses in free space. As for Loss by sea surface reflection, firstly, We ignore the effects of earth curvature on the transmission to simplify the model, then we add the earth curvature and obtain the energy loss of transmission of over the horizon; in the second part, we take the refraction and reflection in ionosphere into account; In the third part, with the basic theory, we draw the conclusion that the energy loss of radio waves transmitted in the free space is proportional to the distance and the radio frequency. we give the energy loss formula of the three parts.