Several OTH radar systems were deployed starting in the 1950s and 1960s as part of early warning radar systems, but these have generally been replaced by airborne early warning systems.
几个OTH雷达系统在20世纪50年代和60年代开始部署，用于部分的早期预警雷达系统，但是这些一般都被空中早期预警雷达系统代替了。