Which parameter, when increased, will generally increase the radar's range, assuming other factors remain constant?

• A. Wavelength
• B. Pulse width
• C. Frequency
• D. Antenna Size

Answer: (C)

Range in radar is determined by how the transmitted energy and the returning echo scale with the wavelength. In the standard radar equation, the maximum detectable range grows with the wavelength roughly as the square root of λ (R ∝ sqrt(λ)) when transmitter power, antenna gains, target reflectivity, and receiver sensitivity are held constant. Since frequency and wavelength are inversely related (f = c/λ), increasing frequency shortens the wavelength and thus tends to reduce range, not increase it. Among the options, increasing wavelength directly lengthens the detectable range.

Antenna size and pulse width can also influence range—larger antennas increase gain, and longer pulses carry more energy per pulse—but their effects are not as universally applicable as the direct λ-dependence.