Over-the-Horizon Radar. It is used as early warning radar applications. His briefing included an overview of the ROTHR mission, specific wind turbine radar interfere\ nce issues associated with the radars, and potential mitigation options. The Over The Horizon Radar operates in HF frequency range from 5 to 30 MHz. MADRE at the Chesapeake Bay Detachment. Let us understand how it works. The OTH radar can detect objects as far as 1000 to 3000 Km. Like other radar system, OTH radar transmits powerful … This webinar featured a briefing from Mr. Larry Nelson, Director Relocatable Over-The-Horizon-Radar \(ROTHR\) at the Forces Surveillance Support Center \(FSSC\). As it detects the objects beyond the radar horizon range with the help of ionosphere, it is known as Over-the-horizon or OTH radar.