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一、前言由于50年代初发现了超视距的对流层散射UHF和SHF传播效应,使得在相邻站距为200—350km的距离上建立对流层无线中继线路成为可能:若传播条件良好,邻站间距可达690—800km。1953年—1967年是TRRL发展的第一阶段。在此期间开通了10万多公里的固定TRRL、推出了许多移动系统并建立了几条黑白电视传输线路。为此目的,研制成功了1—10kW的连续方式发射设备、噪声温度为100—200K低噪参放的接收设备、口面达1600米~2的天线、FL门限扩展解调器以及抑制信号多径造成衰落的系
I. INTRODUCTION Since the discovery of trans-horizon trans-horizon UHF and SHF propagation effects in the early 1950s, it is possible to establish tropospheric wireless trunks at distances of 200-350 km between adjacent stations. If the propagation conditions are good, Up to 690-800km. 1953-1967 is the first stage of TRRL development. During this period, more than 100,000 kilometers of fixed TRRLs were launched, many mobile systems were introduced and several black and white television transmission lines were established. To this end, the successful development of the 1-10kW continuous mode launcher, noise temperature 100-200K low-noise parachute receiving device, the mouth of the antenna up to 1600 m ~ 2, FL threshold expansion demodulator and the suppression of multi-signal The path of decline caused by the Department