What is the length in feet of a 1-wavelength antenna at 28.0 MHz?

• A. 33.4 ft
• B. 66.9 ft
• C. 16.7 ft
• D. 50.0 ft

Answer: (A)

A 1-wavelength antenna length matches the signal’s wavelength. Use λ = c / f. With c about 3.00×10^8 m/s and f = 28.0 MHz (28×10^6 Hz), λ ≈ 3.00×10^8 / 28×10^6 ≈ 10.7 meters. Converting to feet (1 m ≈ 3.281 ft) gives ≈ 10.7 × 3.281 ≈ 35 ft. So the expected full-wavelength length is about 35 feet. Among the choices, 33.4 feet is the closest reasonable match to that value, making it the best choice given typical rounding of constants. The exact value rounded differently still centers around 35 feet, and 33.4 ft reflects that approximate rounding.