使用两付60米的活动铁塔,在2、6和7.6GHz的频率上,在华北、华中、东北和华东的31段地面微波视距电路上进行了绕射传播实验。导出了在未知大气k因子和障碍高度的情况下将天线高度-损耗曲线转化为相对余隙-损耗曲线的公式,根据实验结果给出了不同地形和地面障碍物的绕射损耗予测模型。 Two 60-meter active towers were used to perform diffraction propagation experiments on 31, ground-based microwave horizon circuits in North China, Central China, Northeast China and East China at frequencies of 2, 6 and 7.6 GHz. The formula of converting antenna height - loss curve into relative clearance - loss curve under unknown k factor and obstacle height is deduced. Based on the experimental results, the diffraction loss prediction models of different topographic and ground obstacles are given.