HF/DF stands for Huff-Duff, a system used to locate submarine radio transmissions. Which option correctly identifies the acronym?

• A. Huff-Duff
• B. HF/DF (Huff-Duff)
• C. High Frequency Detection Forward
• D. Heavy Frequency Defense

Answer: (A)

The system is best known by its nickname Huff-Duff, which came from how crews would say HF/DF aloud and then use this term in reports and daily chatter. In practice, Allied forces used Huff-Duff to describe the high-frequency direction-finding equipment and operations that tracked submarine radio transmissions. While the technical expansion of the acronym is High Frequency Direction Finding, the name Huff-Duff became the iconic label of the method used to locate U-boat transmissions during the fight in the Atlantic. This nickname captured the everyday reality on ships and shore stations, where the technique involved taking bearings from multiple stations and triangulating the submarine’s position to guide escort vessels to its location. The other options refer to terms that aren’t the common or historical name for the system.