在视线距离之内,电台间的通信,比如主台和流动通信车的通信,普遍地采用甚高频和特高频.然而,如果需要建立几百公里,即在视线距离之外的通信,可以利用高频电波从电离层反射这一点加以实现.辐射波和反射波大体上都在垂直方向传播.因此,必须采用垂直辐射的天线. Within line-of-sight distances, inter-radio communications, such as master and mobile communications, commonly use VHF and UHF frequencies. However, if hundreds of kilometers need to be established, that is, out of line of sight, The use of high-frequency waves can be reflected from the ionosphere to achieve this point. Radiation and reflected waves are generally transmitted in the vertical direction. Therefore, we must use vertical radiation antenna.