Radio Theory Practice Test 2026 – Comprehensive Exam Prep

Wavelength is found from the speed of light divided by frequency. When you’re using feet and hertz, use the speed of light expressed in feet per second, about 984,300,000 ft/s. So the wavelength in feet is λ (ft) = 984,300,000 / f (Hz). This division reflects the inverse relationship between wavelength and frequency: higher frequency means shorter wavelength. For example, at 3 MHz, λ ≈ 984,300,000 / 3,000,000 ≈ 328 ft. Using frequency in the numerator or a much smaller constant would misplace the units and give the wrong result, and multiplying by frequency would also be incorrect.