A radar with a shorter pulse width will have which effect on minimum range?

• A. Increase minimum range
• B. No change in minimum range
• C. Decrease minimum range
• D. Depends on the target

Answer: (C)

Minimum range is set by the blind time after transmission during which the radar cannot listen for echoes. That blind time corresponds to how far the transmitted pulse travels out and back, so the minimum range is roughly the distance light covers during the transmit pulse divided by two: R_min ≈ c × (pulse width) / 2. If you shorten the pulse width, the blind time shortens, and the radar can begin listening sooner, reducing the minimum range. For instance, halving the pulse width roughly halves the blind range. The target doesn’t affect this limit; it’s all about the transmitter’s pulse duration and the receiver becoming active. Shorter pulses thus decrease the minimum range.