一、前言关于在试验煤矿巷遭中进行的150MH_z和400MH_z 频带的电波传播试验结果等在(第1报)中已作了报导。根据这些试验结果和理论分析,高频带电波传播的优越性已很明显了。这次,试验局用与第1报中同样的试验方法,进行了800MH_z 频带的电波传播试验。关于这些试验结果等的叙述将在本报告中进行。在这些试验煤矿中得到的试验结果与 I. INTRODUCTION The results of radio wave propagation tests in the 150MH_z and 400MH_z bands carried out in coal mine tunnels have been reported (No. 1). According to these test results and theoretical analysis, the superiority of high frequency wave propagation is obvious. This time, the Bureau of Testing used the same test method as reported in the first report to conduct a radio propagation test in the 800 MHz band. The descriptions of these test results and others will be made in this report. The experimental results obtained in these pilot mines are as follows