Operating which radio in high power may result in Electromagnetic Interference (EMI)?

• A. UHF Radio
• B. VHF Radio
• C. AN/ARC 164 (HF Radio)
• D. AN/ARC 220 (HF Radio)

Answer: (D)

High-power RF transmissions can create EMI by radiating energy that couples into aircraft electronics. HF radios operate at lower frequencies and require substantial transmit power for long-range communications, so their RF energy couples more readily into the helicopter’s wiring and onboard systems. Among the options, the AN/ARC-220 is an HF transceiver capable of higher power, which means operating it at high power has the greatest potential to cause EMI with other avionics and electrical systems. The other radios operate at higher frequencies or with less power in typical use, so they pose a lower EMI risk in comparison.