Statistical study on VHF Over-the-horizon propagation characteristics from Kunming to Qingdao

The low end of VHF has HF propagation characteristics, which is called HF up-banding. Based on the measured data of 30MHz~56MHz radio wave propagation in The Link from Kunming to Qingdao for a whole year (From July 15, 2020 to July 14, 2021), the maximum observed frequency and occurrence time of up-banding phenomenon propagation in short-wave are analyzed statistically. The results show that in summer, the probability of up-banding phenomenon is the highest in daytime, the maximum can reach about 70 percent, the up-banding phenomenon basically occurs from sunrise to sunset, and almost no up-banding phenomenon occurs at night. In the whole year, except for the period from May to August, the probability of up-banding phenomenon is very small in other times. In the period from May to August, the maximum probability of up-banding phenomenon greater than 40MHz is up to 50.7 percent, and the maximum probability of up-banding phenomenon greater than 50MHz is 31.4 percent, and the probability of high frequency phenomenon is high.