What must the control operator of a repeater operating in the 70 cm band do if a radiolocation system experiences interference from that repeater?

  1. Cease operation or make changes to the repeater to mitigate the interference
  2. File an FAA NOTAM (Notice to Airmen) with the repeater system's ERP, call sign, and six-character grid locator
  3. Reduce the repeater antenna HAAT (Height Above Average Terrain)
  4. All these choices are correct