What is the effect of a shorter pulse width on radar detection?

• A. Reduces minimum range for close-in detection and improves resolution
• B. Increases maximum range
• C. Degrades display
• D. No effect

Answer: (B)

Shorter pulse width means the radar emits a briefer burst, shortening the time window in which echoes can return. This directly improves range resolution, because the distance between two targets that the radar can distinguish is tied to how long the pulse lasts. In practical terms, range resolution is roughly proportional to the pulse duration, so cutting the pulse width halves the range cell size and lets you separate targets that are closer together along the line of sight.

It also reduces the minimum detectable range, since the closest range you can resolve is set by the length of the transmitted pulse. A shorter pulse translates to a smaller blind zone, allowing detection of objects that are physically closer to the radar.

On the flip side, the energy in each pulse is E = peak power × pulse width. With the same peak power, a shorter pulse carries less energy, which can reduce the maximum range because weaker echoes may fall below the detection threshold. Maximum range can be maintained or increased only if you increase peak power or otherwise compensate for the lower pulse energy.

So, a shorter pulse width primarily improves range resolution and reduces the minimum range, rather than increasing maximum range.